Mya Le Thai is a scientist studying at the University of California. She recently discovered a process that may result in batteries that last forever. Thai said she had been frustrated that the batteries for her wireless devices degrade(退化). Over time, they fail to charge fully. She decided to do something about that problem.
At first, she and her team thought about inventing a new battery. But as they experimented, Thai discovered something that might permit lithium-ion batteries(锂电池) to last forever. Lithium-ion batteries power most wireless devices. Over time, the batteries lose the ability to hold a charge. One of the reasons lithium-ion batteries degrade is their use of nanowires(纳米线) to carry electricity. Nanowires are extremely thin. Nanowires are extremely efficient carriers of electricity, which makes them useful in batteries. But Thai said their thinness also makes them weak. “Nanowires break over time,” she said. “That’s why they lose capacity.”
But, Thai had a theory: The nanowires might last longer if covered with a gel(凝胶). She and the team tested her theory. The team tried many coverings for the wires. PMMA was one of them. The PMMA coated nanowires showed no evidence of damage. The results suggest that batteries could last forever, without losing charging ability. Thai hopes to continue her research to understand why this gel works so well and to see if any other gel could create better results.
Mya Le Thai told VOA she is enjoying the publicity about her discovery. She said she never expected her research to get media coverage. “It’s kind of cool,” she said. “I’m really glad people are showing interest in my work and not just in the work itself, but also in technology and energy.”
1.Why did Mya Le Thai make up her mind to settle the problem about her wireless devices degrade?
A.Because her wireless devices couldn’t work at all.
B.Because she discovered a new kind of battery.
C.Because the batteries for her wireless devices couldn’t last long.
D.Because she wanted to show her new research.
2.What prevents lithium-ion batteries from lasting forever?
A.PMMA. B.Nanowires.
C.Electricity. D.Power.
3.How can the scientist make the nanowires last longer?
A.By using a gel to cover them. B.By cutting them shorter.
C.By making them longer. D.By using a gel to make wire.
4.What kind of person is Mya Le Thai?
A.Generous and wise. B.Honest and wise.
C.Honest and hard-working. D.Modest and creative.
With an improved economy，many travelers have been buying first or business class seats，leaving fewer for upgrades（升级）.Here are some strategies for getting a free upgrade.
1. Fly a lot.
This is the most common way to earn a free upgrade. Most airlines reserve some spaces for travelers who fly at least 5，000 miles per year. Five years ago，this meant half or more of domestic（国内的）first class travelers sat up front for free. But now，airlines are selling more high-price seats，so on popular routes it is not unusual for more than 20 travelers to compete for one or two upgrades. But on routes with fewer business class travelers，free upgrades remain more plentiful.
2. Use miles.
If you're not a frequent traveler but still have some miles to fly，you may be able to use them for an upgrade. Be careful，though，as many airlines now ask not just for miles but also a cash co-pay. One example: on flights to Europe，American Airlines charges 5，000 miles，plus $110，for a one-way upgrade from discounted economy class to business class. For most domestic upgrades，American Airlines wants 15，000 miles plus $ 75.
3. Get lucky.
Sometimes airlines overbook coach（经济舱），and a few travelers get no seats. Agents try to ensure the airline's most loyal travelers get the nod（被选中）. Agents usually have some flexibility to make sure the plane is full and takes off on time. So it's the easiest way for them to do it-they might upgrade someone else out of order.
4. Save a life.
Flight attendants don't usually upgrade passengers, even when empty seats remain. Doctors and nurses who answer an emergency call are sometimes an exception. If they comfort a passenger, flight attendants might allow them to sit in business or first class for the rest of the flight.
1.What might be the main topic of the passage?
A. The ways to get upgraded on a plane.
B. How to get on the flight safely and on time.
C. The best ways to get free flight tickets.
D. How to save a life on a plane quickly.
2.Who can have the chance to get a free upgrade?
A. The person who always obeys the rules on the flight.
B. The person who doesn't have to look after a patient.
C. The person who is a friend of the flight attendants.
D. The person who flies a lot and has a long flying distance.
3.Why might medical personnel be allowed to sit in business or first class sometimes?
A. Because they would like to talk with flight attendants kindly.
B. Because they want to have a better rest after a long journey.
C. Because they need to treat a passenger who is in emergent condition.
D. Because they are tired of staying with common passengers.
4.Where can we find the passage?
A. A life guide. B. A travel guide.
C. A shopping guide. D. A pilot guide.
阅读下面短文，根据其内容写一篇60词左右的内容概要。
If you're worried that too much “screen time ”could badly influence your child's intelligence， new research suggests you might be right. By analyzing the data gathered from over 4，500U. S. kids aged 8 to 11 between 2016 and 2017，Jeremy Walsh，a postdoctoral fellow with the CHEO Research Institute in Ottawa， found that too much “screen time” could be harming your child's intelligence.
Kids with the sharpest intellects spent less than two hours a day on their cellophanes， tablets and computers coupled with 9 to 11 hours of sleep and at least an hour of physical activity. Too much screen time could be affecting kids ability to focus， especially if they are switching between apps on a device or between different screens at the same time， Walsh suggested. “ One leading theory is that much time on screens is spent multitasking using multiple apps or devices at once，” he said. “This can interfere with a child's ability to focus and keep interest on a task. It can be damaging the building blocks for good cognition(认知).”
Sleep is important for brain development， since that's when the brain reorganizes itself and grows， Walsh added. Besides， exercise has been shown to increase blood flow to the brain and oxygenation of brain tissues， and increases the connectivity of networks in the brain. Too much screen time could lead to a“ cascade”(瀑布) effect where kids don't get enough sleep and then are less active during the day.“ You can see how this would have an impact on brain health，” Walsh said.
What should parents do? Walsh advised setting firm rules about the use of screens including how long children are using the screens， the kinds of apps they are using and how many screens they are using at once. Concerned parents also should preview games or apps before letting their child play， seek out more interactive(交互的)options that engage the child's mind， and use parental controls to block or filter content and limit screen time.
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
假如你是李华。你已和英国朋友Eric约定于本周三下午去高铁站接他。但你临时有重要会议不能如约前往，将委托他人接站。请你用英语给Eric写一封致歉信，主要内容包括：
1. 表示歉意；
2. 解释原因；
3. 接站安排。
注意：
1. 词数80词左右；
2. 可适当增加细节，以使行文连贯。
___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。
The Amazon is key to the health of the entire planet. It is the largest rainforest in the world, 1. (rough) half the size of the United States. Statistics show that nearly 20% of the oxygen 2. (produce) by the Earth’s land comes from the Amazon rainforest. It also puts an enormous amount of water into the atmosphere at a time 3. cities are drying up. The Amazon is sucking in carbon and greenhouse gases while slowing the rising temperatures. 4. it’s now burning at a record rate - with images from space 5. (show) the smoke covering much of Brazil.
It’s not the only major forest in danger Nearly half of the world’s forests that 6. (stand) when humans started farming are now gone. The chief reason is the expansion 7. agriculture into forested areas. In Brazil it’s cattle ranching, soy production and logging, according to Nigel Sizer, tropical forest ecologist. “It is responsible for 80% to 90% of 8. loss of tropical forests around the world.” Environmental groups say these activities can 9. (slow) in a much more sustainable way.
However, you can help reforest parts of the world through the Rainforest Trust and Rainforest Alliance. The Rainforest Trust allows you to restrict your donations to a specific project. The Rainforest Alliance says 100% of your 10. (contribute) will help stop deforestation in Brazil right now.
When it rains, my mother and I like to sit in the car, neither of us wanting to brave the rain to get to the house. We always have our best ________ in her little blue Honda, ________ raindrops race down the windscreen and listening to the rain ________ the car roof. I don’t know why, but sitting in the car, we always talk more than ________.
There was one rainy day when my mom told me something that is going to ________ me forever. Earlier that day she and my dad had been ________ about something; I can’t remember what. So she said, “Don’t spend your life looking for Prince Charming. ________, find yourself a really good frog.” At the time, I found this thought really ________. Who wants to think that you’ll never find Prince Charming? Another thought that ________ my mind: if my mom says there’s no Prince Charming, then what’s my dad? A frog? I asked her, and she replied with, “________! If he were Prince Charming, he wouldn’t snore, would be able to cook, and we would never argue. But you know what? He’s a damn good frog.” Being young, I didn’t think of the meaning ________ what she was saying.
But a few years later, I understand the ________ of my mom’s words. You can’t expect everything to be ________. Let’s be completely honest; if you ________ your whole life for your prince with flowing hair, attractive ________, and a white horse, you’re going to be lonely. I think that the ________ of finding a good frog is that you ________ something that’s great, imperfect and all. In life, we can’t afford to wait years for perfection ________. So I think that the best frog you can find is what we’re really looking for in this world. Don’t laze through life waiting to live ________ ever after, because I don’t think you’ll be very happy with the ________.
This I believe.
1.A.debates B.conversations C.memories D.comments
2.A.noticing B.admiring C.watching D.scanning
3.A.strike B.surround C.knock D.attack
4.A.necessary B.accessible C.reasonable D.normal
5.A.count on B.reflect on C.stick with D.correspond with
6.A.arguing B.thinking C.worrying D.dreaming
7.A.However B.Anyway C.Therefore D.Instead
8.A.discouraging B.exhausting C.amazing D.inspiring
9.A.slipped B.crossed C.changed D.searched
10.A.Forget it B.Never mind C.Of course D.No trouble
11.A.about B.over C.within D.behind
12.A.value B.effect C.concern D.weight
13.A.realistic B.perfect C.mature D.reliable
14.A.wait B.advocate C.devote D.challenge
15.A.power B.alternative C.appearance D.belief
16.A.approach B.difficulty C.potential D.point
17.A.expect B.accept C.assume D.confirm
18.A.in time B.in return C.in vain D.in general
19.A.regretfully B.happily C.peacefully D.casually
20.A.reply B.relationship C.intention D.outcome
