A butterfly's wings can have many jobs besides keeping the insect in the air. They may be called on to attract mates, to warn potential enemies to stay away, to do other animals or even to provide disguise（伪装）.
All of these roles, though, depend on their colouration—which is unchanging. This plays into the idea that butterfly wings are dead tissue, like a bird's feathers or a mammal's hair. In fact, that is not true. For example, in some species males' wings harbour special cells that release chemicals which attract females.
Nanfang Yu, a physicist at Columbia University, in New York, has been looking into the matter. One of his interests is the optical（光学的）properties of biological materials. That has led him to study butterfly wings in more detail. And, in cooperation with Naomi Pierce, a butterfly specialist at Harvard University, he has now shown, in a paper published this week in Nature Communications, that butterfly wings are, indeed, very much alive.
Initially, Dr Yu and Dr Pierce wanted to know how the insects keep their body temperatures up without their wings overheating.
Unlike birds and mammals, butterflies do not produce enough internal heat to metabolize（新陈代谢）. Instead, they rely on outside heat sources—usually the sun—to bring their bodies up to speed. But their wings, being thin protein membranes（膜）, have a limited thermal capacity. Those wings can therefore overheat quickly if the insects are exposed to the sunlight too long, or, oppositely, can cool down too rapidly if they are flying through cold air.
In their experiments, the two researchers used a laser（激光）to heat up spots on the wings of dozens of butterfly species. When the temperature of the area under the laser reached 40℃ or so, the insects responded within seconds by doing things that stopped their wings heating up further. These actions included a butterfly turning around to minimize its exposure to the laser, beating its wings or simply walking away.
1.What's Dr Yu's discovery about butterfly wings?
A.They contain dead tissue.
B.They are too thin to store heat.
C.They have different functions.
D.They react quickly to high heat.
2.Which of the following is True according to the text?
A.Butterflies metabolize completely with its internal heat.
B.Chemicals from butterfly wings help drive away threats.
C.The color of butterfly's wings keeps fixed.
D.The researchers achieved big in optical properties.
3.How can a butterfly stop its wings overheating?
A.By providing heat itself.
B.By flying through cold air.
C.By removing the source of heat.
D.By adjusting their heating surface.
4.What's the best title for the text?
A.A Research into Butterfly Wings
B.The Jobs of Butterfly Wings
C.Butterfly Wings: Dead or Alive
D.Butterfly Wings Temperature Changes
Screen time increases by 300 percent between the ages of 1 and 3 according to a recent study. In a perfect world, parents would always choose outdoor time over screen time. But for many parents, decreasing screen time isn't as simple as it sounds. That's because screens are increasingly used as an entertainment and distraction（分心）tool for kids which parents think is necessary due to a lack of quality childcare.
The United States government defines affordable childcare as care costing no more than 7 percent of a family's total income, yet more than 40 percent of families say they set aside more than 15 percent of their total income for it, according to a 2019 survey published by Care. com.
Affordable childcare in America is a dream. “Screen time is used as a last substitute for childcare for many families,” says licensed child therapist（治疗师）Katie Lear. “Particularly for parents who work from home, it can be hard to justify hiring a caregiver or paying for daycare. And yet children need to be able to keep themselves occupied during important work calls. Turning on the TV can buy the parent some valuable time during what can be a very tiring day."
If affordable childcare wasn't just a daydream, if the system we have wasn't dependent on two incomes, if parents could actually afford not to work 50+ hours a week, if childcare centers could afford to pay their workers a desirable wage, then maybe, we'd see screen time decrease instead of increase. We know our kids should be interacting with something other than You Tube videos and flash games for hours a week. But before we fix our broken system and before affordable, quality childcare becomes a reality, parents and caregivers are going to do whatever they can to make it, and that includes using screens as passive childcare.
1.Why do parents allow their children to spend much time on screens?
A.To please their children.
B.To make up the lack of quality childcare.
C.To attract kids' attention to classes online.
D.To help children learn about necessary technology.
2.What do the statistics in Paragraph 2 indicate?
A.Childcare workers have high income.
B.Childcare centers are popular in America.
C.Childcare is a heavy burden for parents.
D.Childcare is supported by local government.
3.Why is Lear mentioned in the text?
A.To uncover the reason for screen time as childcare.
B.To prove the advantages of adopting c-products.
C.To present the ways of parents' improving childcare.
D.To explain the benefits of hiring a caregiver.
4.What's the key in reducing children's screen time?
A.Enough company time. B.High income in the family.
C.Turning off the TV. D.Hiring a caregiver.
In the 1970s, chemist James Lovelock and microbiologist Lynn Margulis developed the Gaia hypothesis（盖亚假说）: all organic and inorganic components on the planet are part of one self-regulating system, working to maintain life on earth. Scientists agree that we need take significant action to control emissions（排放）. But where scientists and popular movements have thus far failed to convince the world to act, it seems that Mother Earth may have succeeded, with the never-before-seen COVID-19.
COVID-19 is estimated to have reduced carbon dioxide emission in China by a quarter. It caused factories to shut down, and slowed construction activities. Recent analysis shows a 70 percent drop in flights in February compared with January. And even getting into a car and going to a restaurant, shopping mall, or concert poses a risk of infection, which means that many people are choosing to stay at home and are consuming less, resulting in a significant reduction of their carbon footprints.
Of course, China and the rest of the world will hope to restart normal production and consumption as soon as the virus is under control. However, some positive measures have already been taken as a result of COVID-19. As the virus is thought to originate from wildlife, Chinese authorities are revising laws and regulations regarding the country's massive wildlife trade in order to prevent future epidemics（流行病）—a win for biodiversity.
The deaths of thousands of people worldwide should also serve as a lasting reminder of the fragility of life. We humans frequently ignore or repress uncomfortable thoughts of death and extinction. We would rather get on with our lives as usual, thinking everything will somehow work out in the end. Only in the face of suffering and death are we forced to view the bigger, longer-term perspective—and this is what is needed in order to react appropriately to climate change. COVID-19 has sent alarm bells ringing throughout the world.
1.What does the author mention the Gaia hypothesis for?
A.To tell the main idea of the text.
B.To introduce the topic for discussion.
C.To show the need to protect the planet.
D.To stress the importance of self-regulating system.
2.What is the second paragraph mainly about?
A.The unexpected benefit of COVID-19.
B.The economic influence of COVID-19.
C.The preventive measures for COVID-19.
D.The possible causes of COVID-19.
3.What does the underlined word "repress" in the last paragraph refer to?
A.Control. B.Hold.
C.Vary. D.Test.
4.What does the writer want to tell us in the text?
A.It's urgent to fight the virus.
B.The virus has caused many deaths.
C.Life is fragile in face of disasters.
D.Action is needed for climate change.
Four Inspiring Movies
Forrest Gump（1992）
Forrest Gump is a simple man with a low IQ but good intentions. This movie follows the fictional story in which the simple man makes his way through some of the more turbulent（动荡的）times from the 1960s through 1980s. This film took home six Oscars, inspired a “Weird Al” song, and proves that a big heart is the most important thing.
It's a Wonderful Life（1946）
No movie list would be complete without a nod to the past. Let's go with this Christmas classic, about a man with serious financial troubles who intends to commit suicide（自杀）by jumping off a bridge. His guardian angel Clarence Odbody stops him and tells him what life would have been like for those close to him had he never been born. Realizing how much he means to others, he rushes back home and all sorts of happy, inspirational, Christmassy things happen.
Dead Poet's Society（1990）
John Keating（Robin Williams）is a high school English literature teacher at a famous all-male boarding school who gets into trouble with the school administration after encouraging his students to challenge authority and think for themselves. It is certainly inspirational, if not also frustratingly sad.
A Beautiful Mind（2001）
This movie tells the story of John Nash（Russell Crowe）, a professor at Princeton, a US university, who revolutionized the field of game theory and fell into madness as a result of paranoid schizophrenia（精神分裂症）. With the love and support of his family as well as the help of medical professionals, he managed to overcome his mental illness and continued to make contributions to the field of mathematics.
1.What can we know about It's a Wonderful Life?
A.It proves a big heart important.
B.It has a happy ending.
C.It tells a story of friendship.
D.It is famous for the leading role.
2.Which film are Robin Williams' fans more likely to watch?
A.Forrest Gump. B.I's a Wonderful Life.
C.Dead Poet's Society. D.A Beautiful Mind.
3.At the end of A Beautiful Mind，the professor___________.
A.became a famous expert in psychology
B.got his family's support for studying game theory
C.gained lots of experience in treating schizophrenia
D.defeated the disease and went on to pursue maths
假定你是李华。你的英国朋友George来信，询问你的近况及上大学准备报考什么专业。 请你回复邮件，内容包括：
1. 正在认真备考；
2.学医学专业；
3.报考理由。
注意:1.词数100左右；
2.可以适当增加细节，以使行文连贯。
Dear George,
___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Yours,
Li Hua
假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共 有10处语言错误,每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏字符号(∧),并在其下面写出该加的词。
删除:把多余的词用斜线(\)划掉。
修改:在错的词下画一横线，并在该词下面写出修改后的词。
注意：1.每处错误及其修改均仅限一词。
2.只允许修改10处，多者(从第11处起)不计分。
Dear Jim,
How is everything going? Known that you are curious about Peking Opera, I'm more than glad to introduce it to you.
Dating back to late 18th century, Peking Opera becomes fully developed and recognized during the Qing Dynasty. As a combination of music, vocal performance or dance, Peking Opera can offer audience with a feast for the eyes and ears. Performer wear colorful costumes and make-ups, that are in line with the personalities of the roles that they play.
I high recommend you visit the Mei Lanfang Theater to see a Peking Opera show. Hopefully, my introduction has helped you well understand Peking Opera than before. If you have any question, don't hesitate to ask myself.
