1 . Grand Canyon Park Ranger Programs
Guided Cedar Ridge Hike
7 am Daily (Meet at the South Kaibab Trailhead)
A 3-mile(4.8km)hike on an unpaved path. Allow 4 hours. Minimum 2 liters of water per person. Bring salty snacks, sunscreen, and wear hiking shoes. Not recommended for people with heart problems, or difficulty walking.
Fossil Discovery Walk
9 am Daily(Meet at the Bright Angel Trailhead sign)
Walk among sea creatures that lived on this part of the continent 270 million years ago, before the age of the dinosaurs. This easy 1/2-mile(0.8 km)one-way walk explores an exposed fossil bed.
Critter Chat
9:30am Daily(Meet at Grand Canyon Visitor Center)
Learn about some of the Grand Canyon's diverse wild creatures who survive here in this place of extreme changes in exposure and climate. Wheelchair accessible. Family friendly.
Geology Walk
3:30 pm Daily(Meet at Yavapai Geology Museum)
Learn how the Grand Canyon formed while exploring Yavapai Geology Museum during this short introductory talk. Why is it so deep, wide, and grand? Why does it exist only here and nowhere else in the world? Consider walking the Trail of Time following the program.
Note: Children must be accompanied by an adult in all programs. All programs are free of charge.
1. What might you do in the program starting at 7 am?| A．Go on a hike. | B．Look for dinosaur fossils. |
| C．Learn more about climate change. | D．Walk the Trail of Time. |
| A．Guided Cedar Ridge Hike. | B．Fossil Discovery Walk. |
| C．Critter Chat. | D．Geology Walk. |
| A．At the South Kaibab Trailhead. | B．At the Bright Angel Trailhead sign. |
| C．At Grand Canyon Visitor Center. | D．At Yavapai Geology Museum. |
2 . Chinese scientists applied a specially developed new technology to laser-ranging (激光测距) telescopes, which enabled them to identify space waste more effectively than previous techniques, according to a study published in the Journal of Laser Applications. “After improving the pointing accuracy of the telescope through a neural (神经的) network , space debris (碎片) with a cross sectional area of one square meter ( 10 square feet) and a distance of 1 ,500 kilometers (932 miles ) can be identified," Tianming Ma, an author of the study from the Chinese Academy of Surveying and Mapping, Beijing and Liaoning Technical University, Fuxin, said in a statement.
Debris can include non-functional spacecraft, abandoned launch vehicle stages, and other mission-related space waste. It is very dangerous for astronauts and spacecraft in orbit above the Earth as they travel very fast — up to 18,000 miles per hour. Worryingly, there are probably many millions of tiny debris pieces in low-Earth orbit, and tens of thousands larger than a softball, NASA said. Fortunately, there have been surprisingly few collisions.
Laser-ranging technology has previously been used to find space waste. However, these systems have their limitations when it comes to accurately identifying small, fast-moving pieces. In fact, previous laser-ranging methods have only been accurate to within about 0. 6miles.
In an attempt to overcome the inaccuracies in laser-ranging techniques, the Chinese team used so-called neural networks to improve the effectiveness of their telescope system. Neural networks are computing systems which are inspired by biological networks in the brain. They can learn to become better at tasks without being given a specific set of rules to follow. Ma and his team tested this method against more traditional techniques at the Beijing Fangshen laser range telescope station. According to the team, this is the first time that neural network has been used to significantly improve the pointing accuracy of a laser-ranging telescope. They say that the latest findings could have significant meaning for guiding spacecraft in orbit.
1. What are laser-ranging telescopes designed to do?| A．Set up a neural network in space. |
| B．Find out the precise position of space waste. |
| C．Help the telescopes work more accurately. |
| D．Confirm the amount and size of space waste. |
| A．Useless man-made objects in space. | B．Fast-travelling softballs. |
| C．Launch vehicle stages in low-Earth orbit. | D．Satellites moving too fast. |
| A．Rule followers. | B．Biological computing. |
| C．Machine learning. | D．Spacecraft guidance |
| A．New Technology Used to Find Space Waste |
| B．The First Telescope to Handle Space Debris |
| C．An Invention for Astronauts and Spacecraft |
| D．The Substitute for Laser-ranging Telescopes |
3 . Wildlife Crossing Bridges
The Wildlife Bridge
In 2018, Utah built a wildlife bridge over the busy highway 1-80. A 4.8-kilometer fence was created to help guide animals to the bridge. Normally, animals take a long time to discover and begin using wildlife bridges, so experts didn’t expect the bridge to get much traffic for several years. But recently, they’ve discovered many different kinds of animals are beginning to move by using the bridge.
The Rope Bridge
On China’s Hainan Island in 2015, scientists created a bridge for Hainan gibbons that are the world’s most endangered primates and normally cross the forest by swinging high in the trees. But after a 2014 typhoon, landslides caused huge gaps in the forest, which were forcing the gibbons to make dangerous jumps. Scientists created a simple and cheap rope bridge, which settled the problem.
The Eco-Bridge
In Uttarakhand state in India, the forest department has built a special "eco-bridge" , made from all-natural materials. It’s 27.5 meters long and runs over one of the busiest highways in the area. Though the bridge is high in the trees, forest department workers hope the bridge will help smaller animals on the ground, too. Already, the bridge has gotten a lot of attention on the Internet, with many people taking photos in front of it every day.
The Park Bridge
The Phil Hardberger Park lies in San Antonio, Texas, and recently it has opened what they say is the largest wildlife bridge in the US. This bridge, unlike the others mentioned here, was built for use by both animals and humans. The park says they have already seen deer using the bridge.
1. What has made experts feel unexpected about the Wildlife Bridge?| A．It’s been completed within 2 years. | B．It’s being used by animals already. |
| C．It’s become an Internet-famous site. | D．It’s America’s biggest wildlife bridge. |
| A．The Wildlife Bridge and the Eco-Bridge. | B．The Wildlife Bridge and the Rope Bridge. |
| C．The Eco-Bridge and the Park Bridge. | D．The Rope Bridge and the Park Bridge. |
| A．To attract more tourists. | B．To reduce traffic accidents. |
| C．To save endangered animals. | D．To create wildlife passageways. |
4 . Research has shown that disrupting one's natural “morning lark” (早起鸟) or “night owl” (夜猫子) tendency can result in immoral behavior at work.
Who doesn't love a flexible work schedule? Being able to make your own hours, come in when you're ready and leave when you're done, step out to attend a child's presentation at school, have a midday appointment, or even squeeze in a quick workout or nap as a guaranteed pick-me-up — flexibility greatly improves one's quality of life.
The benefits don't stop there, however. Research has shown that having flexible work hours actually makes one a better person. How so? It's been found that disrupted sleep patterns —in the form of having to act outside of your normal inclination to be a morning “lark” or a night “owl” — can result in strange, unethical, and out-of-line behavior.
Science journalist Linda Geddes said, “If you don't get enough sleep, research suggests you are more likely to have unethical behavior, such as being mean, bullying your fellow employees or falsifying receipts. But it's not just owls: the larks tend to behave more unethically in the evening, and owls in the morning. So ideally, you want to introduce flexible working."
Employers would be wise to allow their employees to start whenever they feel ready — whether it's at the crack of dawn or at 11 a.m., and to allow breaks or pauses in the day as needed — because that would mean better productivity, performance, and behavior.
This shift is already happening, with the New York Times recently reporting that 27 percent of US employers now offer the flexibility to work outside normal business hours, up from 22 percent in 2014; and 68 percent allow telecommuting as needed (up from 54 percent in 2014). With the national unemployment rate at its lowest in 50 years, employers are having to become more competitive in what they offer workers, and flex-hours seem like a no-brainer, highly beneficial to all.
1. What is mainly talked about in Paragraph 2?| A．Ways to improve life quality. |
| B．People's activities in their free time. |
| C．Methods to get a flexible work schedule. |
| D．The advantages of flexibility in work time. |
| A．Judgment. | B．Tendency. | C．Reaction. | D．Choice. |
| A．They will show their nature more easily. |
| B．They tend to suffer from sleep problems. |
| C．They tend to behave immorally in their work. |
| D．They will get more flexibility in working time. |
| A．The unemployment rate is increasing. |
| B．Employers are getting more free time. |
| C．Flexible working has been creating more jobs. |
| D．More employers adopt a flexible work schedule. |
5 . Covid-19 has brought a great deal of trouble for all of us since March 2020. During this time, mobile phones have been the solution for the boredom and restlessness caused from staying indoors. The most downloaded apps on play store 2020 are;
TikTok
TikTok was the most downloaded app. With over 111.9 million downloads, TikTok has seen a huge growth in 2020, twice more than what it got in 2019. 20% of its total downloads were from India and around 9. 3% of the total downloads were in the US.
Zoom
Zoom was the second most installed app in the overall downloads category. With nearly 94. 6 million installs, Zoom is the most used app for online meetings and virtual classrooms. 17% of its downloads were in the US and India. Offices and educational institutes were shut down and to continue working and studying from home, people relied heavily on Zoom for video conferencing and calling.
WhatsApp ranked third in overall downloads with more than 100 million downloads. It is one of the most popular and widely used chat applications; WhatsApp also supports communication between international phone networks.
It ranked fourth in the overall downloaded list. Facebook is the world’s most popular social networking application. Facebook builds technologies that give people the power to connect with friends and family, find communities and grow businesses.
1. What do we know about TikTok?| A．It is an India-based app. | B．It has most users in America. |
| C．It is used for growing business. | D．It has doubled its download than in 2019. |
| A．TikTok. | B．Zoom. | C．WhatsApp. | D．Facebook. |
| A．Communication. | B．Training. | C．Teaching. | D．Payment |
6 . English Language Courses at ELC Los Angeles
At the English Language Center (ELC) Los Angeles you will find a variety of English courses and programs that meet the highest academic standards of any English language school in the United States. Through its 40 years of teaching students at all levels from all over the world, ELC has developed teaching and training techniques and programs that really work for everyone.
ENGLISH COURSES OFFERED AT ELC LOS ANGELES
● GENERAL ENGLISH COURSES
Intensive English Course
Semi-intensive Course
Individual Intensive Course
● TEST PREPARATION COURSES
Cambridge Preparation Course
TOEFL Preparation Course
● BUSINESS ENGLISH COURSE
Individual Executive Business English Course
ENGLISH CLASSES LOS ANGELES FACT FILE
● Length of lesson: 50 minutes
● Number of levels: 12
● Average number of students per class: 8-9
Maximum number of students per class: 10 (14 during July and August only)
ADDITIONAL SERVICES AT ELC LOS ANGELES
The ELC Los Angeles staff is eager to assist international students in achieving their long-term learning goals. ELC offers the following support services to ensure each student's time at ELC is enjoyable, effective and worry-free:
● Student Visa
ELC has been approved by the Department of Homeland Security (DHS)to issue the SEVIS Form I-20. Students enrolling in a minimum 24-lesson-per-week course are eligible (有资格的) to receive an I-20 form in order to apply for an F-1 student visa in their country.
● English Level Evaluation with Multi-level- Placement
Each student benefits from our English level evaluation with multi-level placement. Our method means students usually have different teachers for different levels and ensures that students study English in the learning environment that is best for them.
● University Admission Services
ELC is pleased to offer free counseling and university placement services to all ELC students interested in continuing their education at an American college or university in California and around the United States.
1. Which course should you choose in order to improve your English in general?| A．TOEFL Preparation Course. | B．Individual Intensive Course. |
| C．Cambridge Preparation Course. | D．Individual Executive Business English Course. |
| A．8. | B．10. | C．12. | D．14. |
| A．To help achieve enough class hours. | B．To help start from the lowest level. |
| C．To help get into an appropriate level. | D．To help gain admission to university. |
7 . When Adora Svitak was twelve years old, she spoke on the TED stage, saying she hates the word "childish" if it's being used to describe irrational （不合理的）demands or irresponsible behavior. She said she has seen enough of that in the adult world, so she knows irrational demands and irresponsible behavior aren't limited to children. In fact, she made the point that adults could learn a thing or two if they'd only open their mind to the possibility that kids have a lot to offer the world.
Even as a kid, Svitak often spoke to educators, making the point that there should be more of a reciprocal （互惠的）relationship between teachers and students. "It shouldn't just be teachers at the head of the classroom telling them to do this or that. The students should teach their teachers," she said.
But she wasn't naive（幼稚的）, and she knew that isn't how many classrooms and schools operate in that way. Her theory is that it's all about trust. Adults always seem to have a restrictive （约束的）attitude towards kids. "Kids have no or very little say in making the rules," Svitak joked.
As a young child, Svitak loved to write. When her mom gave her a computer she wrote over 300 short stories on it. She wanted to get them published, and she was lucky because her parents were on her side. Even though she was turned down by many publishers, eventually she did have a book of short stories published. She was only seven years old then.
After that first success, Svitak has gone on to do more impressive things, something she wishes more kids had the support to do. She says it's important for kids to be heard and contribute when they're young, so they grow up to become a better kind of adult. "The goal is not to turn kids into your kind of adults, but rather better adults than you guys have been. Progress happens because new generations and new eras grow and develop, and they become better than the previous ones. It's the reason we aren't in the Dark Ages anymore," she said.
1. What does Svitak think of using "childish" to describe irrational demands?| A．It is unfair for children. | B．It can lead to positive effects. |
| C．It takes no account of adults' needs. | D．It can result in irresponsible behavior. |
| A．Students get along with teachers. | B．Students teach instead of learning. |
| C．Teachers keep telling students what to do. | D．Teachers and students learn from each other. |
| A．They supported her. | B．They had doubt about it. |
| C．They were greatly shocked. | D．They hardly took it seriously. |
| A．Children need to stick to their dreams. |
| B．Parents should satisfy their children's needs. |
| C．Children are advised to imitate their parents. |
| D．Parents should support and expect more from children. |
8 . A living robot has been created out of frog skin cells. Xenobots, named after the frog species Xenopus laevis that the cells come from, were first described last year. Now the team behind the robots has improved their design and demonstrated new capabilities.
To create the xenobots, Michael Levin at Tufts University in Massachusetts and his colleagues obtained tissue from 24-hour-old frog embryos after very small physical operation. Where the previous version relied on the contraction of heart muscle cells to move them forward by pushing off surfaces, these new xenobots swim around faster. They also live between three and seven days longer than their previous generation, which only lasted about seven days, and have the ability to sense their surroundings to some extent, turning red when exposed to blue light.
“The fundamental finding here is that when you free skin cells from their normal context, and you give them a chance to build other things than what they normally build,” says Levin. “To me, one of the most exciting things here is that they are plastic. This idea that even normal cells, not genetically modified, are in fact capable of building something completely different.”
Because they are created from cells, the xenobots eventually break apart and are totally biodegradable, says team member Douglas Blackiston, also at Tufts University. He therefore hopes that they can be used for biomedical and environmental applications.
Previous attempts at creating living robots, such as a wirelessly controlled cockroach, have involved dealing with live animals, raising ethical concerns. Xenobots differ from these because they are made entirely of living cells. “The approach here is maybe ethically the least problematic because everything starts with cells. They have no neurons, so it's not an animal,” says Auke ljspeert at the Swiss Federal Institute of Technology at Lausanne, who wasn't involved in the research. “It's really cells, so I find it maybe the cleanest way."
1. How were the new xenobots created?| A．By making use of frog embryos. | B．By relying on heart muscle cells. |
| C．By sensing similar surroundings. | D．By exposing them to blue light. |
| A．Fragile. | B．Stable. | C．Flexible. | D．Active. |
| A．The xenobots can't break down easily. | B．The xenobots need to be further perfected. |
| C．The xenobots can be applied in other fields. | D．The xenobots have already been widely used. |
| A．The new approach starts with some neurons. |
| B．Xenobots have raised least ethical concerns. |
| C．The wireless controlled cockroach is a failure. |
| D．Previous living robots involve few living animals. |
9 . Just like humans, birds too rely on sound to communicate. However, they do not have a “language” in the true sense of the word and instead produce a variety of sounds to convey different emotions.
Often, birds recognize their mates(or young) by sound rather than sight. Hungry young birds use begging calls to let their mothers know it is feeding time. Alarm calls, flight calls and warning calls are other sounds made frequently by adults.
A new study shows that songbirds rehearse(排演) their songs even in their sleep. The activity in the brain of the birds when asleep is similar to the brain activity when the birds were awake and singing. The team used tiny recording devices to measure the activity of individual brain cells in four songbirds both when they were singing and when they were asleep.
Apparently the bird stores a song after hearing it, and then rehearses it later in its sleep. Scientists now believe the birds “dream of songs and tunes” to help them master the fine art of singing and that sleep plays a key role in the learning process!
Many songbirds learn to sing listening to adult birds of the same species. However, if separated from the adults, the young birds develop sounds which are hard to understand instead of normal song patterns. Researchers carried out an experiment in which a male bullfinch (灰雀) was raised by a female canary(金丝雀). The bullfinch soon learned the canary’s song and when it was later mated to a female bullfinch, Mr.Bullfinch taught his children the canary’s songs.
Last year, a British survey of London’s songbirds showed that the city’s birds are losing their tunes. Birds could hardly hear one another, over the traffic noise; as a result, instead of copying the sweet notes of the adults, young birds were copying the sounds they heard most often, namely car horns and beeping cellphones!
1. According to the passage, birds recognize their mates by ________.| A．using their own words | B．listening to their sounds |
| C．looking at their appearances | D．singing the same songs |
| A．Flight calls. | B．Alarm calls. |
| C．Begging calls. | D．Warning calls. |
| A．young birds learn to sing from whom they live together with |
| B．birds only learn how to sing from the same adult species |
| C．it's not easy for adult birds to teach young birds songs |
| D．a canary's song is more beautiful than a bullfinch's |
| A．traffic noise makes young birds become deaf |
| B．birds in the city can sing as sweetly as those in the wild |
| C．birds in the city recognize their mates mainly by sight |
| D．noise pollution causes much trouble for birds in the city |
10 . Tracking wildlife is a tough job. Take the case of a one-eared leopard named Pavarotti.
Kasim Rafiq, a wildlife biologist at Liverpool John Moores University. “So I used to get up at the crack of dawn, follow his tracks and try and find him. So one day, I went out, and I was looking for him. And his tracks took me off road through this woodland area...and...”
Before he knew it, the wheel of his Land Rover was stuck in a deep hole. He wasted several hours getting it out. And then, on the way back to camp, he came across some local tour guides and their safari (观赏野兽的旅行) guests, who’d had way better luck spotting Pavarotti. “Basically, they laughed and they talked to me that they’d seen him that morning.”
Rafiq then realized that tourist wildlife sightings might be an untapped source of information about wild animals.
So he and his team worked with a safari lodge in Botswana to analyze 25,000 tourist photographs of wildlife. They compared those data to the estimates they made with traditional wildlife biology methods.
It turned out that the estimates from tourists’ photos were just as good as those gleaned (四处搜集) from traditional methods. And the tourists were actually the only ones to see elusive (难以捉摸的) leopards — the researchers would have missed the cats without the citizen science data. The results are in the journal Current Biology.
The idea is not to put wildlife researchers out of a job. “The reality is there are so many interesting things we still have to find out about these large carnivores (食肉动物) and so many conservation (保护) projects that need to be carried out that we don’t have the time or resources to do them all.” And tourist photos might help make sure that all the local carnivores are spotted.
Thanks for listening for Scientific American-60-Second Science. I’m Christopher Intagliata.
1. What happened to Rafiq when he tracked Pavarotti?| A．He was lost in the woods. |
| B．He was trapped in a deep hole. |
| C．He found Pavarotti with tourists’ help. |
| D．He met Pavarotti on the way back to camp. |
| A．The photos are sources of information about wildlife. |
| B．The photos are mirrors of the wildlife researchers’ life. |
| C．The photos taken by tourists are of high quality. |
| D．The photos taken by tourists are especially beautiful. |
| A．The researchers have missed the data of cats. |
| B．The information from tourists’ photos was equally good. |
| C．The value of tourist photos hasn’t been proven. |
| D．Only the traditional methods can track wildlife. |
| A．On TV. | B．In a magazine. | C．On a radio. | D．In a book. |
