When a laptop or smartphone battery starts lo...

When a laptop or smartphone battery starts losing its power, the only options are to buy an expensive replacement or just keep it plugged in all the time. But a woman Mya Le Thai may have found the solution to this problem.

Thai was frustrated that the batteries for her wireless devices degraded (退化) over time, until they failed to charge fully. She did not like having to keep her laptop connected to an electrical outlet to keep it powered on. So, she decided to do something about that problem. At first, she and her team at UC Irvine thought about inventing a new battery. But as they experimented, Thai discovered something that might permit lithium-ion (锂离子) batteries to last forever.

Lithium-ion batteries power most wireless devices. Over time, the batteries lose the ability to hold a charge. Most of these batteries have a lifespan of about 7,000 charging cycles before they die. One of the reasons lithium-ion batteries degrade is their use of nanowires to carry electricity. Nano wires are extremely thin. A human hair is thousands of times thicker, for example. Nano wires are extremely efficient carriers of electricity, which makes them useful in batteries.

But, Thai had a theory — the nanowires might last longer if covered with a gel (凝胶). She and her team tested this theory. “It was a long process and a lot of work,” Thai said. The team tried many coverings for the wires. PMMA, a type of plastic, was one of them. The nanowires were coated with PMMA and cycled through charging 200,000 times. 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 and 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 work on lithium-ion batteries?

A.She disliked the batteries for her laptop.

B.Her team were ordered to invent a new battery.

C.Many people thought batteries were too expensive.

D.The batteries would soon fail to get fully charged.

2.What can we infer about nanowires?

A.They are too weak to carry electricity.

B.They are not suitable to use in batteries.

C.They Iasi exactly 7,000 charging cycles.

D.Their thinness is a cause of batteries degrading.

3.What was Thai and her team’s breakthrough?

A.Coating nanowires in a gel. B.A new kind of battery.

C.New materials for batteries. D.A new way of charging batteries.

4.What may be the best title for the passage?

A.Mya Le Thai discovered nanowires B.A woman invents a lasting battery

C.The options of batteries for wireless devices D.The reasons for batteries degrading

高二英语阅读理解中等难度题查看答案及解析

What did the man want to do?

A.Buy a new battery. B.Charge his phone. C.Use a laptop.

高二英语短对话中等难度题查看答案及解析

When you’re new to a school or campus, your smartphone will be your new beat friend. Here are four kinds of apps to help you get started in the US.

1. Social media: 1. You can use Facebook to communicate with various groups or people that share a common interest. Apps like Snapchat are more for close friends. Instagram focuses on photos you share. Twitter limits you to 280 character per “tweet,” or post. 2.

2. Ride-sharing: Need a ride? 3. Then you will find out how far the nearest ride is to your location and how much it will cost to get where you want to go. The app is linked to your bank account, so you don’t have to worry about carrying cash.

3. Eating: Don’t want to get off the couch（沙发）or move away from your desk? Order from almost any nearby restaurant, pay online, and wait for a delivery driver to bring it to your front door through Grubhub, UberEats or DoorDash. 4.

4. Texting/Phoning Home: College students like to communicate in groups, which makes messaging apps common on campus smartphones. 5. But using apps like WhatsApp, GroupMe or Slack for calls or texts makes it cost-effective on a student’s tight budget.

A. Type your destination into Uber or Lyft.

B. That’s because it can help you make many friends.

C. Therefore, you learn to be brief, to the point and clever.

D. Turn to the computer for help and search for the destination.

E. And cellphone carriers may charge high fees for international calls.

F. This is great for students who don’t have a car or the time to fetch food.

G. These are the big ones in the US: Facebook, Twitter, Instagram and Snapchat.

高二英语七选五中等难度题查看答案及解析

–Do remember to charge the battery 12 hours when you first use it.

--_________.

高二英语单项填空简单题查看答案及解析

It is a live celebration of the lasting power of letter writing!

Letters Live, which started in December 2013, was held at the Freemasons’ Hall in London from March 10 to 15. The show invited various great performers who read remarkable letters that had been written around the world over the centuries.

“Bringing letters alive through outstanding performances is one of the most powerful ways in which the joy and pain and humor and tragedy of being human can be shared,” Jamie Byng, managing director of Canongate Books publishing firm, told the Nowness video channel.

British actor Benedict Cumberbatch agreed. “Letters are windows into the love, beauty, pain and humor of their creators and receivers,” he told The Guardian. “Letters Live makes us stop and imagine the lives behind the letters read and where they came from. It’s a privilege to read this most ancient of communications live to an audience.”

This year, the movie Sherlock star treated the audience by playing the part of a 17-year Tom Hanks. He put on the young actor’s voice when he read his letter to the Hollywood director George Roy Hill, a letter that urged Hill to “discover” him. The letter revealed that two-time Oscar winner Hanks’ teenage dream was not to “be a big-time Hollywood superstar” but to one day own a Porsche car and call his favorite US actor Robert Red ford his nickname “Bob”.

Other famous faces at the event included Carey Mulligan, who played a fictional laundry worker, a female activist fighting for women’s rights in the 2015 movie Suffragette. The British actress once again played the role of a suffragette, when she read a very enthusiastic letter demanding the vote for women. The suffragette sent a precious 1913 note to The Daily Telegraph newspaper.

“Everyone seems to agree upon the necessity of putting a stop 10 Suffragist anger, but no one seems certain how to do so,” Mulligan read out. “There are two, and only two, ways in which this can be done. Both will be effectual. One, kill every woman in the UK. Two, give women the vote.”

1.What was Cumberbatch’s attitude’ towards Jamie Byng’s opinion?

A. Doubtful.　　 B. Positive.

C. Optimistic.　　 D. Cautious.

2.Which of the following was a dream of Tom Hanks as a child?

A. To become an actor.　　 B. To call himself “Bob”.

C. To win Oscar Awards.　　 D. To have a famous car.

3.A “suffragette” is a woman who 　　　　 .

A. sends a valuable note to newspaper.

B. reads out a letter to the audience.

C. advocates women’s right to vote.

D. plays a famous role in a movie.

4.What can be a suitable title for the text?

A. Famous People Gathering.

B. Letters of Great Performers.

C. Letters Brought to Life.

D. Rights Given to Women.

高二英语阅读理解中等难度题查看答案及解析

Living gratefully has a huge transforming power, not just when something wonderful or special happens, but every day no matter what is happening.

I’ve recently been involved with two people whose lives were challenged by bad luck. I have seen how grateful living had the power to keep one of them going and how it’s beginning to lift the other. One was a friend and the other is my sister.

My friend seemed to be in good health when she received a deadly diagnosis: a disease with no effective treatment. She had all the emotions that a tragedy brings, but she also had a powerful response to despair (绝望) that gave her “the happiness that doesn’t depend on what happens.” She wrote online daily, honestly sharing the details of her situation.

She wrote that even though it was difficult to move, this gave her more time to notice small things. She was grateful not only for the love and help of family and friends, but also for time to see the sun rise and watch the birds in her yard. No opportunity for gratefulness was wasted.

She taught that gratefulness is not a false cheerfulness. It’s taking every opportunity to celebrate the blessings of small things. We can be grateful for the challenges that help us develop sympathy for each other. Life is a precious gift.

She repeatedly blogged that she was happier than she had ever been.

When she wrote about “the worst day”, she ended with “life is still a lovely gift.” She died later that day.

Her message, however, changed my sister’s life. My sister’s health was getting worse and worse, though nothing life-threatening. She did have a very painful knee. Her life was in danger from her defeated spirit. She was bed-bound (卧床不起), getting weaker and weaker. Fearful, angry and depressed, she felt out of options for recovery.

I read my sister a few of my friend’s messages. I was careful not to say, “Why can’t you be more like her?” Instead, I let the words do their work. I’m grateful to say that an attitude of gratitude began to replace her anger and fear. I believe this helped her to heal.

We can’t be grateful for all that happens, but we can practice gratefulness for life itself, for all we can learn to deal with, for all the ways we can help each other grow and heal.

1.What happened when the author’s friend found she had an incurable disease?

A.She complained that life was unfair to her.

B.She started to appreciate and enjoy the small things in life.

C.She tried her best to look for treatment.

D.She repeatedly blogged about how painful it was.

2.How did the author’s sister feel when she was ill?

A.Calm. B.Lonely. C.Sad. D.Confused.

3.What does the underlined “this” refer to in the article?

A.Writing a blog. B.Eating healthy food.

C.Talking with family. D.Being grateful for life.

4.What message does the article mainly convey?

A.A friend in need is a friend indeed.

B.Gratitude has the power of lifting people’s spirits.

C.Health is the most important thing for people.

D.Families will always be there no matter what happens.

高二英语阅读理解中等难度题查看答案及解析

How to clean your dirty laptop

You know your laptop is dirty, But when's the last time you cleaned it? 1.. The keys are clean, the screen is free of smudges(污迹) and you fall in love with that three-year-old laptop all over again.

Gather your supplies

“You don't need much to clean a computer,” said Jolie Kerr, a cleaning expert. “I use exactly found things to keep my laptop clean: Rubbing alcohol, microfiber cloths, cotton swabs(棉签) and canned air.” 2.. They'll work fine, but they’re probably overpriced compared with what you have at home.

Start with the inside

3.. If there are visible dust bunnies in the vents, you' re let it go far too long without a cleaning In that case, you may want to open it up or take it to a repair shop for an in-depth cleaning.

Wipe down the outside

4.. “The most critical thing when cleaning a laptop or desktop computer is to app the cleaning product to the tool you're using to clean, never ever directly onto the computer” Ms. Kerr said.

Get rid of bad smell

Let's say you have a particularly terrible case of dirty laptop, and even after the above steps, your laptop still carries the bad smells. Getting rid of those is a challenge. 5.For that you can turn to the world's best natural deodorize(除臭剂): Charcoal.

A. Next comes the fun part: Making that laptop shine again.

B. Then, take your computer apart and check it carefully.

C. Don’t bother with specialty cleaners you see at electronics stores.

D. Once you’ve gathered your tools, it's time to start cleaning the inside.

E. They also make nice add-on gifts for those in need of a new computer.

F. Cleaning the surface can help, but a lot of those smells may also be inside.

G. Using a freshly cleaned laptop is almost as satisfying as getting a new one.

高二英语七选五中等难度题查看答案及解析

When people lose legs after accidents or illnesses, emergency care and artificial limbs（假肢）often allow them to walk again. Newts （蝾螈） in the same situation, on the other hand, can grow limbs back on their own! Scientists have known for a long time that certain animals can re-grow limbs, but they haven’t quite figured out how these creatures do it.

Researchers have now come up with some new ideas. Their work may give people the ability to re-grow lost limbs. The researchers started with two simple experiments：when you cut a newt’s leg at the ankle, only the foot grows back；when you cut off a leg at the very end, the whole leg grows back. In both cases, the re-growth begins with stem cells. Stem cells can develop into nearly any type of cell in the body.

How do a newt’s stem cells know when to grow only a foot and when to re-grow a whole leg?

This question relates to another mystery. In newt’s, a cut-off leg will grow back only if the nerve bundle（神经束）in it also grows back , but if something prevents the nerve bundle from growing, the stem cells at the wound won’t re-grow a new leg.

In its study, a British team focused on a protein called n-AG. When the team prevented nerves in a limb from growing, but added the n-AG protein to stem cells in the limb, the limb still re-grew. That protein seems to guide limb re-growth. People have proteins that are similar to n-AG. Further research into these materials may someday help human limbs recover by themselves.

40. In the experiments, the researchers cut off a newt’s foot or leg to find out _____.

A. what stem cells were                    B. whether they would grow back

C. how long it would take to re-grow    D. how they would re-grow

41. A newt will re-grow its leg if _____.

A. its ankle was cut off but the nerve bundle was good

B. its leg was cut off and the nerve bundle stopped growing

C. its leg was cut off and the nerve bundle could grow back

D. its ankle and the nerve bundle were cut off

42. What do the underlined words “these materials” refer to?

A. Nerve bundles and proteins.         B. Proteins similar to n-AG.

C. Stem cells and proteins.              D. Stem cells and nerve bundles.

43. The first sentence of the passage _____.

A. acts as a lead–in                      B. shows where researchers got their new ideas

C. states the author’s opinion           D. describes the result of researchers’ studies

高二英语阅读理解简单题查看答案及解析

Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

“To provide enough power, we need certain methods with high energy density (密度)”，said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope (放射性同位素) battery can provide power density that is much higher than chemical batteries.”

Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro/nanoelectromechanical systems (MNEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.

“People hear the word ‘nuclear’ and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems.”

His new idea is not only in the battery’s size, but also in its semiconductor(半导体). Kwon’s battery uses a liquid semiconductor rather than a solid semiconductor.

“The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure(晶体结构) of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem.”

Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery, In the future, they hope to increase the battery’s power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

1.Which of the following is TRUE of Jae Kwon?

A. He developed a chemical battery.

B. He teaches chemistry at MU.

C. He made a breakthrough in computer engineering.

D. He is working on a nuclear energy source.

2.Liquid semiconductor is used to ________.

A. reduce the damage to lattice structure

B. test the power of nuclear batteries

C. decrease the size of nuclear batteries

D. get rid of the radioactive waste

3.According to Jae Kwon, his nuclear battery ________.

A. uses a solid semiconductor

B. will soon replace the present ones

C. could be extremely thin

D. has passed the final test

4.The text is most probably a ________.

A. book review

B. science news report

C. newspaper ad

D. science fiction story

高二英语阅读理解困难题查看答案及解析

Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

“To provide enough power, we need certain methods with high energy density(密度)”, said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope(放射性同位素) battery can provide power density that is much higher than chemical batteries.”

Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro / nanoelectromechanical systems (M/NEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.

“People hear the word ‘nuclear’ and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems.”

His new idea is not only in the battery’s size, but also in its semiconductor(半导体). Kwon’s battery uses a liquid semiconductor rather than a solid semiconductor.

“The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem.”

Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery. In the future, they hope to increase the battery’s power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

1.Which of the following is true of Jae Kwon?

A. He teaches chemistry at MU.

B. He is working on a nuclear energy source.

C. He developed a chemical battery.

D. He made a breakthrough in computer engineering.

2.Jae Kwon gave examples in Paragraph 4_________.

A. to introduce nuclear batteries can be safely used

B. to show chemical batteries are widely applied

C. to introduce various energy sources

D. to describe a nuclear-powered system

3.Liquid semiconductor is used to _________.

A. get rid of the radioactive waste

B. test the power of nuclear batteries.

C. reduce the damage to lattice structure.

D. decrease the size of nuclear batteries

高二英语阅读理解中等难度题查看答案及解析