1 . “Have you ever heard that it’s impossible to fold a piece of paper more than seven times? Actually, it is just a popular myth.

The myth refers to folding a piece of paper in half many times in any direction. The paper is folded in half. Try it for yourself with a piece of notebook paper. ________ But when you make the fifth and sixth folds, you’ll notice that it’s increasingly hard to fold the paper. Why does it happen? Because the number of the layers (层) of paper doubles with each fold. For example, after the sixth fold, you’re left with 64 layers of paper. If you have strong hands, you may be able to make that seventh fold. If you start with a piece of paper that is 0.01 centimeters thick, it’ll be as thick as a notebook after seven folds. And it would seem impossible to make more folds. At this point, you may be thinking that the paper-folding myth doesn’t sound much like a myth.

However, in 2002, a high school student named Britney Gallivan proved the idea wrong. Britney successfully folded a 1.20-meter-long roll of toilet paper 12 times (note that she used single-direction folding). She also developed a math rule. This is convenient. It allows you to find out the maximum (最大的) number of possible folds based on paper thickness, paper length, and direction of folding.

Since Britney’s success, many people have managed to fold a single piece of paper more than 7 times. Students even folded a piece of toilet paper a total of thirteen times. The toilet paper they used was about 4,000 meters long!

A．

B．

C．

D．

2 . One day, you open the fridge and find some moldy (发霉的) food. But before you can throw it away, your mother stops you. She doesn’t want to waste it, so she cuts off the moldy part and eats the rest. Is it safe to do this?

Mold can grow on almost all kinds of food. It is usually green, white, black or gray. Mold makes food soft and changes its color. Moldy food tastes quite bad and it’s not safe to eat.

If you find mold in soft food, just throw it away. Soft food, such as bread, tomatoes or hot dogs, usually contains (含有) water, which allows mold to grow easily below its surface. Bacteria (细菌) can also grow along with it.

But it’s easy to remove mold from hard food because mold can’t grow very deep inside this kind of food. According to BBC news, you should cut about 2.5 cm around and below the mold to remove it. It’s OK to cut the moldy parts out of hard food and eat the rest. But if the food is completely covered with mold, you should, still throw it away.

Most kinds of mold are bad for us. But some kinds of mold can be used to make food. For example, penicillium (青霉菌) can be used to make many types of cheeses, such as blue cheese. These cheeses are safe to eat and they’re quite delicious as well.

“Dreams may be more important than sleep. We all need to dream.” Some     1     say.

Dreams take up about one quarter of our     2     time. People have several dreams each     3    . Dreams are like short films. They are usually in color. Some dreams are like old     4    . They come to us over and over again. That may be because the dreamer is     5     about something. Dreaming may be a way of trying to find an answer. Some people get new ideas about their work from dreams. They may have been thinking about their work     6     day. These thoughts can go into dreams. Sometimes we wake up with a good     7     from a dream. But often we can’t remember the dream. Dreams can disappear     8     from memory.

Too much dreaming can be harmful. The more we sleep, the     9     we dream.

The mind is still at work     10     we dream. That is     11     we may have a long sleep and still wake up tired.

Everyone wants to have healthy teeth. When you laugh, you will open your mouth and __________ your teeth. The healthier your teeth are, the _________ you feel. Why is that?

It’s _________ your teeth are important in many ways. Take care of _________, and they’ll help to take care of you.

_________ and healthy teeth help you grow. They also help you speak _________. You can take care of your teeth by _________ like these: brush your teeth _________ a day, after getting up and before bedtime. And you should brush all of your teeth, not just the front ones. Spend some time _________ the teeth along the sides and in the back. Take your time while brushing. Spend at __________ three minutes each time you brush. Be sure your toothbrush is soft. Ask your parents to help you get a new toothbrush __________ three months. Clean between your teeth with dental floss（牙线 ）. It feels strange when you do it at first, __________ soon you’ll get used to __________ it. Brushing __________ your teeth healthy. You also need to care about what you eat and drink. Eat __________ vegetables and fruit and drink water instead of drinks.

Do you want to have white and healthy teeth? Please brush your teeth!

If you don’t keep yourself warm enough, winter can be a time to have an     1    . During the winter months, people     2     get colds and flu. Many people think they are the same, but they are     3    . Colds can stay with you for up to a week. You will have a running nose, sore throat, headache, cough and a fever. Flu is     4    . You will feel sick very quickly. You will have a fever and a headache. Your body will hurt and become weak. This could last for up to four weeks. Is there any way to keep yourself     5     from colds and flu? Staying clear of (避开)     6     with colds or flu may work. Try not to touch     7     nose or eyes if you have been close to someone who has a cold. Wash your hands, especially after     8     your nose.     9     out with wet hair can also give you a cold! If you catch a cold or flu, go to bed and rest. Doing this will help you get     10    . Drink lots of water. Stay in a warm, well-aired room. If you have a headache or your muscles hurt, don’t forget     11     some medicine.

7 . People often think of the North Pole and the South Pole as similar frozen wastelands. They are both places with very cold temperatures and few people live there. However, the North and South Poles are not much alike as people may imagine.

The North Pole has no land, only thick ice. Temperatures seldom go above 32°F, at which water turns into ice. Most of the time, it stays below zero. In winter temperatures are usually as low as-30 F.

Although conditions were very poor, people tried for many centuries to reach the North Pole. More than 100 years ago, two men, Robert Peary and Mathew Henson, were able to get to this environment full of troubles and difficulties. They reached the North Pole on March 8th, 1909. It was really a hard trip for them.

There are few things more dangerous than crossing the Arctic on foot. People who stayed there may face many problems: very cold temperatures, sudden storms, and even hunger. Most of the area is uninhabited. Few people can live in such a difficult place.

People might think that with such low temperatures for most of the year, the ice would be thick and hard. However, this is not true in the Arctic. The movement of the ocean water under the ice may often cause many different changes on the surface. Sometimes the ice breaks into two opening lanes of water called “leads”. Anyone who falls into a lead can be frozen to death in a few minutes.

9 . Chaka Salt Lake is in Qinghai Province. It sits at an altitude (海拔) of about 3,100 meters and covers an area of 105 square km. It is rich in salt with a heavy salt bed close to the lake surface. That makes the lake a main source of salt in our country. When the weather is clear, the lake provides beautiful reflections (映像) of the blue sky. That is why people call it “Sky Mirror”.

Because of its amazing views, people see the lake as one of the “must-go” places in China. The best time to visit it would be from July to August. It is believed that breathing in the humid air with its salt content is especially good for the lungs (肺).

If you want to go on a trip to the lake, the following tips may be helpful.

★Don’t eat the salt in the lake directly.

★Wear sunglasses and a hat because of the ultraviolet rays (紫外线).

★Prepare some medicine for the weak and the elderly to deal with altitude sickness.

Traveling to such a beautiful world of salt surrounded by snowy mountains and green grassland, you will feel like you are in a wonderland.

If you have a chance, why not go there and enjoy the amazing place?