Unsolved Mysteries about the Planet Earth
Mystery 1: Where did water come from?
Water covers more than 70 percent of the Earth's surface and that makes the Earth earn the nickname " the blue planet " . Then where di water come from? The most popular scientific theory states that the H2came from several violent asteroids(小行星）covered with ice. Another suggests that the water actually has been around since the Earth's formation However it happened, though, it's certainly worked out well for the Earth life forms.
Mystery 2: What about all the oxygen?
Another thing is the planet's oxygen. Tiny creatures released oxygen as a waste product, filling the atmosphere with it. After that, the level of oxygen in the Earth's atmosphere went wildly up and down until it finally calmed down around 540 million years ago. Since then, it's remained at about the breathable level we know today. But what caused it to be suddenly steady?
Mystery 3:What caused the Cambrian(寒武纪）Explosion?
The Cambrian Explosion refers to the explosion of complex life forms that occurred on Earth about 540 million years ago. Before then, life had consisted mostly of microbes. But at the beginning of the Cambrian period complex creatures began developing at a rate never seen before. Suddenly,life forms had brains, eyes, and bones. Most living creatures today can trace their blood back to the Cambrian period.
Mystery 4: Will we be able to predict earthquakes?
We still haven't been able to come up with a way to accurately predict earthquakes. We can certainly try, but our current technology cannot predict them exactly. We know that earthquakes start when the rock cracks underground and the enormous energy released in the process causes vibration, which generates earthquake waves, but we haven't figured out why that happens, or how to predict it.
1. What was created by creatures on Earth?| A．Water. | B．Bacterium. | C．Oxygen. | D．Ice. |
| A．Mystery 1 . | B．Mystery 2. | C．Mystery 4. | D．Mystery 3. |
| A．It is a matter that has extremely practical significance. |
| B．It will be solved in the near future. |
| C．It is the most difficult mystery to solve of the four. |
| D．It is the oldest mystery of the four. |
相似题推荐
【推荐1】While there are many factors that go into how attractive you are to mosquitoes, new research has found the colors you’re wearing definitely play a role.
That's the main takeaway from a new study published in the journal Nature Communications. For the study, researchers from the University of Washington tracked the behavior of female Aedes aegypti mosquitoes when they were given different types of visual and scent cues (信号). The researchers put the mosquitoes into small test chambers and exposed them to different things, like a colored dot or person’s hand.
In case you’re not familiar with how mosquitoes find food, they first detect that you’re around by smelling carbon dioxide from your breath. That prompts them to scan for certain colors and visual patterns that could indicate food, the researchers explained.
When there was no smell like carbon dioxide in the test chambers, the mosquitos pretty much ignored the colored dot, no matter what color it was. But once researchers sprayed carbon dioxide in the chamber, they flew toward dots that were red, orange, black, or cyan. Dots that were green, blue, or purple were ignored.
“Light colors are perceived as a threat to mosquitoes, which is why many species avoid biting in direct sunlight,” entomologist Timothy Best says. “Mosquitoes are very likely to die by dehydration(脱水), therefore light colors may typically represent danger and prompt avoidance. In contrast, darker colors are similar to shadows, which are more likely to absorb and store heat, allowing mosquitoes to use their sophisticated antenna to locate a host.”
If you have the option of wearing lighter or darker clothes when you know you'll be going into an area with lots of mosquitoes, Best recommends going with the lighter choice. “Dark colors stand out to mosquitoes, whereas light colors blend in.” he says.
Apart from avoiding colors mosquitoes like (red, orange, black, and cyan) when you’re going into areas where these bugs are known to exist, there are other things you can do to lower your risk of being bitten by a mosquito, which include:
·Using insect repellent
·Wear long-sleeved shirts and pants
·Get rid of standing water around your home or empty items that hold water like bird baths, toys, and planters weekly
·Use screens on your windows and doors
Each of these protective measures will contribute in decreasing your likelihood of getting bitten. And, if you’re able to wear something other than red or dark colors, even better.
1. How did researchers from the University of Washington conduct their study?| A．They referred to a series of previous research findings. |
| B．They compared the behavior of female mosquitoes with male ones. |
| C．They exposed mosquitoes to different living environments. |
| D．They kept track of the behavior of some female mosquitoes. |
| A．drill | B．cause | C．require | D．qualify |
| A．You can go out wearing lighter or darker clothes. |
| B．Dark colors do a good job in protecting you from being bitten. |
| C．Light colors make it less likely for mosquitoes to detect you. |
| D．Light colors may represent danger and prompt avoidance. |
| A．Screening your windows and doors. |
| B．Leaving standing water around your home. |
| C．Dismissing carbon dioxide from your breath. |
| D．Wearing clothes in red or dark colors. |
【推荐2】A warm drink of milk before bed has long been the best choice for those wanting a good night’s sleep. But now a study has found it really does help people nod off（打瞌睡）—if it is milked from a cow at night.
Researchers have discovered that “night milk” contains more melatonin(褪黑激素), which has been proven to help people feel sleepy and reduce anxiety（焦虑）.The study, by researchers from Seoul, South Korea, involved mice being fed with dried milk powder（奶粉） made from cows milked both during the day and at night. Those given night milk, which contained 10 times the amount of melatonin, were less active and less anxious than those fed with the milk collected during daytime, according to the study published in The Journal of Medicinal Food.
Night milk quickened the start of sleep and caused the mice to sleep longer.
While the effect of cow milk harvested at different time has not been tested on humans up to now, taking melatonin drugs has been suggested to those who have trouble falling asleep at night.
Previous （以前的）studies have also showed that milk can be excellent for helping sleep because of the calcium content, which helps people to relax.
1. According to the text, the mice fed with daytime milk_______.| A．started sleep more easily | B．were more anxious |
| C．were less active | D．woke up later |
| A．It’s been tested on mice for ten years. |
| B．It can make people more energetic. |
| C．It exists in milk in great amount. |
| D．It’s used in sleeping drugs. |
| A．Night Milk and Sleep | B．Fat Sugar and Health |
| C．An Experiment on Mice | D．Milk Drinking and Health |
| A．By giving examples. |
| B．By stating arguments. |
| C．By explaining statistical data. |
| D．By providing research results. |
【推荐3】When you hear the word “shapeshifting (变身)”, you may think of magic in some movies and not the climate. But that’s what animals are doing to go on living in the world.
A new study shows that some animals are slowly growing larger beaks, legs and ears. In this way they can cool themselves down more easily as the Earth gets warmer. When we talk about the climate change, we often ask “What can humans do with this?” “How can we live in the future?” “But we should know that animals also have to face these changes,” said Sara Ryding, from Deakin University, Australia. If animals do nothing to keep their normal body temperature, they will die.
In one example, the beaks of some kinds of Australian parrots have grown 4 to 10 percent larger. The study says it has a lot to do with the hotter summer over the years. There are other similar examples. Wood mice have longer tails and bats in warm climates have bigger wings.
Although the changes are still small, they could be common as the weather becomes hotter. “Body parts like ears may become bigger, so we might be able to see a real Dumbo (big-eared elephant from a Disney cartoon) in the near future,” Ryding told the reporters.
1. Why do animals grow bigger body parts?| A．To become stronger. | B．To enjoy a better life. |
| C．To find food easily. | D．To keep normal body temperature. |
| A．2. | B．3. | C．4. | D．5. |
| A．Changes. | B．Tails. | C．Wings. | D．Examples. |
| A．Why climate changes so much. | B．When the climate starts to change. |
| C．How animals deal with hotter weather. | D．What the weather will be like in the future. |
【推荐1】Long ago, many people had gardens. Fewer people were interested in having gardens. But in the past few years, this has begun to change. More people are starting to make gardens again. People of all ages are learning the joy of planting. Maybe you would like to start your own garden. It’s easier than you may think.
The first step is making some choices. What sort of plants do you like? What do you want to grow? Many people have flower gardens. People grow these gardens for the way that they look. They are pretty to look at. Flowers can have many shapes and many colors. Other people grow food in their gardens. They grow fruits and vegetables. These gardens are helpful. Some people like both types of gardens, so they have flowers and food.
After you choose the type of garden you want, you’ll need a good location for it. The best place for a small garden is in a yard. One of the most important things to look for is sun. Always put your garden in a sunny spot. You should also put your garden in a place that is easy to get to. And you will want to put flowers in a place where everyone can see them.
Each kind of plant is different. Once you choose the plants you want, you have to learn a little about them. Some plants grow best in spring. Others should be planted in summer. A few plants grow all year long. Choose when you will do your planting. Then choose the best plants to grow.
I’m sure you will enjoy your garden. Gardens can be very pretty. What’s nicer than seeing bright flowers all around you? You can also grow many kinds of great foods. Some people say food they grow themselves tastes better. Best of all, gardens are just plain fun.
1. Now people think planting a garden is _____________.| A．hard | B．boring | C．traditional | D．joyful |
| A．Making choices. | B．Planting flowers. |
| C．Growing food. | D．Buying fruits and vegetables. |
| A．In a cool place. | B．Outside your yard. |
| C．Near a park. | D．In a sunny spot. |
| A．To explain what plants to grow. | B．To tell people how to start a garden. |
| C．To ask people for ideas about gardens. | D．To encourage people to grow their own food. |
【推荐2】Japan is a nation that values silence and good manners. Yet, when it comes to eating noodles, Japanese people can be the loudest in the world.
According to lifestyle website Grapee.jp, slurping (发出喷喷声) when eating noodles is encouraged in Japanese culture. It’s believed that taking air into your mouth can improve the flavor of the noodles and help cool down the food. It’s also considered to be a way to show your preference for the dish. Sometimes, just making the noise alone seems to make the noodles more enjoyable.
It was not until a new expression — “noodle harassment” — came out on social media that Japanese people started to realize the problem. They found that the slurping noise was making some foreign visitors uncomfortable.
As a response, Japanese instant noodle maker Nissin introduced a so-called noise-canceling fork last month. The fork looks like an electric toothbrush. It is connected wirelessly to a smartphone. When the person using the fork starts to slurp, the fork will send a signal to the person’s phone. Then the phone will play a sound to cover the slurping noise.
But is it really necessary? Dining traditions and table manners do vary. In India, people eat with their hands. They think they build a connection with the food in this way. However, people who are used to eating with forks might find it unacceptable to get their hands covered in oil or sauce. But this eating method is part of India’s culture, just as Japan’s slurping is part of its own.
“So, if you are eating noodles, please slurp as you like,” wrote a Japanese food blogger. “If anyone gets annoyed while you are doing that, ignore them. They’re missing the point entirely.”
1. What’s the main idea of paragraph 2?| A．The importance of Japanese culture. | B．The way to improve the taste of noodles. |
| C．The description of cooling down hot noodles. | D．The reasons for slurping when eating noodles. |
| A．Annoyance. | B．Anxiety. | C．Politeness. | D．Preference. |
| A．The fork turns down the slurping noise. |
| B．The fork reminds the user to stop slurping. |
| C．The fork signals the smartphone to hide the noise. |
| D．The fork could be changed into a silent toothbrush. |
| A．To show that forks are unnecessary. | B．To give an example of cultural differences. |
| C．To share a possible solution to slurping. | D．To introduce specific food culture of India. |
【推荐3】The act of making and being a friend is as simple as it is difficult. Here area few tips to help you make new friends as well as to take better care of the friendships you already have.
Remember that people will like you more than you think they will.
Invest in activities that you love. Ask anyone about how to make friends and they will most likely tell you to try a new hobby. It might sound empty, but it works.
Be present. The planet is warming, and there’s so much good television out there to watch. We get it. But if you want to keep your friendships, you have to show up for them.
| A．So don’t listen to it |
| B．Accept the awkwardness |
| C．Do the things you’re enthusiastic about |
| D．You don’t have to be interested in just one thing |
| E．You have to listen and notice things about your friend |
| F．We have a few tips for being present and engaged with your friends |
| G．Actually, this advice is based on a well-known theory and some field research |
【推荐1】Travel Journal
Friday
We arrived in Paris on Friday lunchtime and went straight to our apartment. We then went for a walk around our area and realized how close we were to the centre of Paris. It only took us 20 minutes to walk to the Louvre. After a walk around the Tuileries Gardens, we went for afternoon tea in a café called Angelina which has the most delicious hot chocolate. After warming up we then walked along to the big department store Printemps, on the top floor where you get a wonderful view of Paris (this was free). We walked along a street called Grands Boulevards which was beautiful with all its Christmas lights. The shops on this street are famous for their Christmas window displays. In the evening we cooked at the apartment and went to a Scottish pub which was funny as two of my friends are Scottish.
Saturday
In the morning we went for brunch (a meal between breakfast and lunch) at a really cool café called FAB (French American Bakery). We had waffles with bacon and fresh carrot and ginger juice. We found out that we were really close to a chocolate museum, so of course we took a visit--- who doesn’t love chocolate! In the afternoon we went to a Christmas market with unique handmade gifts and crafts. In the evening we ate at a Tunisian restaurant and had roast chicken and vegetable stew with couscous. It was delicious and the restaurant was in a cute little lane.
Sunday
On Sunday we went for breakfast at the same café and we caught our train back home at midday, carrying shopping bags full of lovely presents that we had bought at the Christmas market. We had a great weekend in Paris. Exploring this beautiful city with no plans was an unusual but great idea as we got to do things we wouldn’t normally discover. I highly recommend spending a weekend somewhere trying to be a local!
1. Where did they enjoy the beautiful view of Paris?| A．In a Scottish pub. | B．In a department store. |
| C．In a café called Angelina. | D．In the Louvre. |
| A．Christmas lights. | B．Delicious food. |
| C．Handmade gifts and crafts. | D．Christmas window display. |
| A．On Sunday lunchtime. | B．On the morning of Saturday. |
| C．On the morning of Sunday. | D．On Friday lunchtime. |
【推荐2】 
At age 12, Keegan Sobilo of New Baltimore carefully tucks his legs and arms into a fire suit, pulls on a helmet and climbs into a race car that exceeds 80 mph. He has been doing this since age 8.
“ At first, I was scared to death. I was like, 'Let's do bowling or swimming. ' It's still very scary.But he knows what he's doing. Your heart goes out on that track every time he goes out there," said his mother Hillary Sobilo.
＂The sixth-grader always wears pajamas to the track every night and takes them off when he puts his race clothes on. He's been doing that for the last four years. That's his trademark,” said Tim Phillips, his crew chief. The first time he wore his train pajamas to the track, Keegan went from last place to ninth place. He decided they brought luck. Since then, he has won a series of championships.
Passion for cars runs in the family. Keegan's father is a design mechanic at Fiat Chrysler Automobiles. He knows what it means to have seats and roll cages built to fit his son's body."What I see in Keegan is passion, like how I feel about car restoration. But for him, everything has to align itself. I tell my son you have to be the perfect package. Winning races every weekend is not the only key. More importantly, you have to have the right name, you have to look the correct way, speak the correct way, and act the correct way. Then the rest of it is really luck, like the stock market. If you don't put yourself out there,you'll never hit it big."
While Keegan's classmates play basketball and volleyball,Keegan is at the Birch Run track-practicing, qualifying and racing until 10 p.m. or 2 a.m. While many children spend time playing video games, Keegan runs race simulation training with his joystick after school.
＂The kid is cool.It was like having a grandson. We showed respect to each other. And he takes it very seriously," said competitor Mike Todd, 69 , of Galesburg, Michigan." He's an older soul in a young man's body. I'd like to see him make it big. He's got the willpower."
1. Keegan enjoys ______| A．swimming |
| B．racing cars |
| C．bowling |
| D．playing games |
| A．Victory. |
| B．Safety. |
| C．Good qualities. |
| D．Real luck. |
| A．Keegan spends a lot of time practicing |
| B．the train pajamas bring Keegan success |
| C．Keegan's mother worries about his studies |
| D．Keegan picked up the hobby at the age of 4 |
Be careful what you say around your dog．It might understand more than you think．
A border collie named Rico recognizes the names of about 200 objects, say researchers in Germany．The dog also appears to be able to learn new words as easily as a 3-year-old child．Its word-learning skills are as good as those of a parrot or chimpanzee．
In one experiment, the researchers took all 200 items that Rico is supposed to know and divided them into 20 groups of 10 objects．Then the owner told the dog to go and fetch one of the items and bring it back．In four tests, Rico got 37 out of 40 commands right．As the dog couldn't see anyone to get clues, the scientists believe Rico must understand the meanings of certain words．
In another experiment, the scientists took one toy that Rico had never seen before and put it in a room with seven toys whose names the dog already knew．The owner then told Rico to fetch the object, using a word the dog had never heard before．
The correct object was chosen in seven out of ten tests, suggesting that the dog had worked
out the answer by process of elimination（排除法）．A month later, Rico remembered half of the new names, which is even more impressive．
Rico is thought to be smarter than the average dog．For one thing, Rico is a border collie, a breed （品种）known for its mental abilities．In addition, the 9-year-old dog has been trained to fetch toys by their names since the age of nine months．
It's hard to know if all dogs understand at least some of the words we say．Even if they do, they can't talk back．Still, it wouldn't hurt to sweet-talk your dog every now and then．You might just get a big, wet kiss in return!
1. From paragraph 2 we know that __________．
| A．animals are as clever as human beings |
| B．chimpanzees have very good word-learning skills |
| C．dogs are smarter than parrots and chimpanzees |
| D．dogs have similar learning abilities as 3-year-old children |
| A．Rico is smart enough to get all commands right |
| B．Rico can recognize different things including toys |
| C．Rico has developed the ability of learning mathematics |
| D．Rico won't forget the names of objects once recognizing them |
| A．Rico has a better memory partly because of its proper early training． |
| B．The purpose of the experiments is to show the border collie's mental abilities． |
| C．The border collie is world-famous for recognizing objects． |
| D．Rico is born to understand its owner's commands． |
| A．To train your dog． | B．To talk to your dog． |
| C．To be careful with your dog． | D．To be friendly to your dog． |
I want to be closer to my mom, but whenever I try to share things with her, she doesn’t understand. Skyline
Dear Skyline,
As we grow up, our interests change a lot. As a teenager, it may just be that your mom and you don’t share the same interests right now. It’s normal for the relationship between teenagers and their parents to become distant for a short while.
If you don’t think your mom understands you or your interests, why not try to get involved in some of hers? If she has a hobby, try to join in with it. For example, if she’s a good cook, ask her to teach you some recipes. If she likes running, go for a run with her.
Likewise（同样地）, try to get her involved in the things that you do often. Invite her to go to the movies or to coffee together, or ask her to help you study some time.
Another great way to get to know your mom better is to ask her about her childhood. My mother has lots of great tales about being a teenager in the 1960s, and hearing her share them and laughing at her funny memories always brings us closer together. Ask your mom about her life as a teenager too I bet she’d love to share her stories
There could be many reasons that your mom might seem too busy to do things with you. She could just be tired from a long day of work, or she may have a problem of her own that’s affecting how she acts toward others.
Whatever happens, don’t worry. She loves you and always will. And hopefully one day soon, you will both understand each other perfectly.
1. What is Skyline’s problem?| A．She doesn’t live close to her mom. |
| B．She doesn’t share things with her mom. |
| C．Her mom is too busy to spend time with her. |
| D．Her mom doesn’t understand her. |
| A．Typical. | B．Unusual. | C．Strange. | D．Tough. |
| A．To encourage her mom to talk to her. |
| B．To give her mom time to think of the past. |
| C．To help her know more about her mom. |
| D．To get her a chance to laugh at her mom. |
| A．Skyline’s mom has a problem of her own. |
| B．Skyline’s mom probably isn’t a good mother. |
| C．Skyline is badly treated by her mom at home. |
| D．Skyline probably doesn’t understand her mom. |
【推荐2】Thanks to Arizona's tax credit program, taxpayers can make a big difference with their dollars. Learn how these four organizations are making a difference and how you, too, can be part of the solution to help the underserved through donations.
Catholic Charities Community Services
Catholic Charities Community Services provides adoption for foster（领养）children as well as education and certification for foster families throughout central and northern Arizona. But they can't do it without your help. You can change the life of a child.
Visit Catholic Charities at www. catholiccharitiesaz. org to learn the impact your gift makes.
Catholic Community Foundation（CCF）
Established in 1983. CCF aims to build the future of faith by providing sustainable support for those who serve the community. Since 1995, CCF has given more than $ 27 million back into the community through donor-advised funds, savings and growth funds, etc.
You can learn more by visiting ccfphx. Org.
Catholic Education Arizona
Catholic Education Arizona has been creating future leaders for 23 years. And it has raised 268 million and awarded underserved youth 138,000 scholarships to change lives, strengthen families and transform culture. With more than $9 million remaining to claim, interested corporations are encouraged to contact our office for more information.
You can learn more by visiting catholiceducationarisona. Org.
The Society of St. Vincent de Paul
The staff and volunteers at the Society of St. Vincent de Paul packaged more than 4,000 meals for individuals and families to pick up on a daily basis. St. Vincent de Paul's family dining room, food boxes, medical and dental care, shelter and other services are nearly 100% funded by private donations. Donors can claim up to $800 in Arizona charitable tax credits.
Learn more at svdptaxcredit. info.
1. Taxpayers can learn more about their charitable gifts to foster children by visiting _________.| A．cefphx. org | B．www. catholiccharitiesaz. org |
| C．svdptaxcredit. info | D．catholiceducationarizona. org |
| A．Serving the community. | B．Supplying food to those in need. |
| C．Aiding foster children or families. | D．Financially supporting underserved youth. |
| A．They only offer service to families. | B．They provide help for patients. |
| C．They bring hope to the underserved. | D．They are profitable organizations. |
【推荐3】For many, choosing the perfect summer holiday destination is no easy job. Here’s why Portugal could prove the perfect summer destination to suit everyone.
Delicious local cuisine(烹饪/菜肴)
Portuguese cuisine is up-and-coming on the world scene, with an abundance of dishes in every shape and flavor. Behind every Portuguese dish, there’s the recipe(烹饪方法) of a mother, of an aunt or an uncle, of a grandmother or a grandfather. The local cuisine is rooted deep in the hearts of the Portuguese people, which is one of the reasons why Portuguese food is so special. Whether it’s at the table of a top restaurant or a traditional inn, the food offers up the unforgettable taste of the Iberian Peninsula. We recommend you try the popular grilled sardines(沙丁鱼) that can be found all over the city’s, traditionally served with a side of boiled potatoes and vegetables or salad.
Take the sun back with you
The summer weather is a huge benefit to Portugal, with over 2, 500 hours of gorgeous sunshine each year. Stepping outdoors to see anything but the beautiful glow of the sun is something you needn’t battle with the indecisiveness of the climate in certain other European destinations.
Holiday-goers can bring back the sun-kissed yellowish-brown color by enjoying the beautiful Marinha beach in the beach capital, Algarve. There’s certainly no lack of inspiration to enjoy a drink in the sun!
Take a dive into a diamond blue joy
The Portugal is famous for its deep blue, and the summer not only offers up the opportunity to enjoy a range of sea-based activity like surfing, but it also allows you to explore the sea world beneath the waves.
Surrounded by cliffs and close to a small fishing village and harbor, Arrifana beach is a popular destination among surfers. Why not head out to the Santa Cruz Ocean Spirit on the 19-28th July? This is an International Wave Sports Festival noted for its national and international sports events like surfing, ski-boarding, wave skiing, and bodysurfing.
The very best kinds of holidays are the ones that do not require a holiday to recover from it!
1. What’s special about Portuguese food?| A．Being loved and shared. |
| B．Being traditionally homemade. |
| C．Enjoying varieties of colors. |
| D．Being served at all corners. |
| A．Taking a drink in the sun. |
| B．Seeing anything but sunshine. |
| C．Celebrating the sports Festival. |
| D．Exploring the sea world. |
| A．Tough. | B．Tiring. |
| C．Relaxing. | D．Adventurous. |
