People have been wondering why elephants do not develop cancer even though they have lifespans (寿命) that are similar to humans, jiving for around 50 to 70 years.
Now scientists believe they know why. A team at the University of Chicago, US has found that elephants carry a large number of genes that stop tumors (肿瘤) developing. To be precise, they found 20 copies of an anti-tumor gene called TP53 in elephants. Most other species, including humans, only carry one copy.
According to the research, the extra copies of the gene improved the animal’s sensitivity to DNA damage, which lets the cells quickly kill themselves when damaged before they can go on to form deadly tumors.
“An increased risk of developing cancer has stood in the way of the evolution of large body sizes in many animals,” the study author Dr Vincent Lynch told The Guardian. If every living cell has the same chance of becoming cancerous (癌变的), large creatures with a long lifespan like whales and elephants should have a greater risk of developing cancer than humans and mice. But across species, the risk of cancer does not show a connection with body mass.
This phenomenon was found by Oxford University scientist Richard Peto in the 1970s and later named “Peto’s paradox (悖论)”. Biologists believe it results from larger animals using protection that many smaller animals do not. In the elephant’s case, the making of TP53 is nature’s way of keeping this species alive.
The study also found that when the same genes were brought to life in mice, they had the same cancer resistance as elephants. This means researchers could use the discovery to develop new treatments that can help stop cancers spreading or even developing in the first place.
“Nature has already figured out how to prevent cancer,” said Joshua Schiffman, a biologist at the School of Medicine, University of Utah, US. “It’s up to us to learn how different animals deal with the problem so that we can use those strategies to prevent cancer in people.”
1.Why are elephants unlikely to develop cancer?
A.They have a rather large body size.
B.Their genes suffer no DNA damage.
C.Certain genes in their body kill existing tumors.
D.They carry many genes to prevent tumors developing.
2.According to the passage, what has been a risk in the evolution of large animals?
A.Deadly tumors. B.The huge body mass.
C.Cells killing themselves. D.Sensitivity to DNA damage.
3.What does the underlined part “This phenomenon” in Paragraph 5 probably refer to?
A.Larger animals have protection from TP53.
B.The risk of cancer is not related to body size.
C.Larger animals suffer the same risk of cancer as smaller ones.
D.The larger animals are, the bigger risk of cancer they will have.
4.What can be concluded from the passage?
A.Depending on nature is surely enough to fight against cancer.
B.The TP53 genes have proved useful in stopping cancer in people.
C.Humans are expected to prevent cancer with the making of TP53.
D.The extra copies of elephants, genes are used to cure cancer patients.
The stories we share with one another are important. They show wisdom and provide inspiration. They are important to our development. But sometimes people choose not to tell.
Consider the negative effects of not sharing a story in the news: People are wondering if public health officials are holding back too much information about the recent outbreak of Ebola.
There is a danger in holding back stories that ought to be told. Bobette Buster said it like this, “The fact is, history has shown us that stories not told can become like a dangerous genie (妖怪) left in a bottle. When they are finally uncorked, their power to destroy is set free.”
There are a number of reasons why we hide parts of our story: they often show our weaknesses or expose our disadvantages; they require courage and strength to share; and of course, there are some stories that should be kept secret—especially those that embarrass someone else.
Most of us have two selves: the one we display on the outside and the one we actually are on the inside. And the better we get at hiding the stories that show our true selves, the more damage we may be causing to ourselves and to others.
Honesty and openness is important: it proves we are trustworthy. It displays we are human. We are not perfect or better. It highlights the importance of hard work and personal development. Hard work may not allow us to overcome our disadvantages completely. But with hard work, we do not have to be restricted to our mistakes.
Does this mean we admit every weakness, every disadvantage, and every secret regret to everybody we meet? No, of course not. There is a time and a place and a certain level of relationship necessary for some stories to be told in an appropriate manner.
1.What’s the function of the example in Paragraph 2?
A.It reflects that people are concerning about the spread of Ebola.
B.It shows the bad effect caused by sharing a story.
C.It proves not sharing a story can cause trouble.
D.It concludes that one should share a story at a proper time.
2.Which is close in meaning to the underlined word “uncorked” in Paragraph 3?
A.freed B.broken
C.unfolded D.untouched
3.One of the reasons why people are unwilling to share experiences is that _______.
A.story-sharing highlights the importance of hard work
B.people are used to exposing their weaknesses
C.people sometimes have no courage to share their stories
D.some stories make themselves feel sad
4.The writer aims to convince us to _______.
A.be open to people close to you by sharing some secrets
B.share stories appropriately for the good of others and ourselves
C.remove the dangers that can be caused by untold stories
D.realize the importance of being honest when making friends
My love for libraries blossomed when I joined the public library. From the age of 8 I was allowed to walk from my home to the downtown library, housed above the police station. Once the librarian gave me my first membership card, I could enjoy a range of books, which started with Little House in the Big Woods. I was addicted instantly, and this love of libraries and reading would change my life, allowing me to one day create a safe space for high-school kids, too.
By the time I was in high school, I could read the authors that we were studying in class, including Charles Dickens, Mark Twain and Emily Bronte. During the summer months, I got caught up in Gone with the Wind.
When I studied English literature at university, I thought it was time to build my own library. For the next 40 years, I continued to collect books. Until one day, I realized that all my books had become a part of the house, like wallpaper.
Toward the end of my teaching career, I became a teacher-librarian at my old high school, where I had first learned English literature. This position enabled me to regain my love and appreciation for libraries. I had a generous budget for my classes, so I searched for novels that would interest my teenage audience and hopefully spark a love of books. Fantasy, science-fiction, graphic novels -I bought almost any type of books that my students wanted to read. I bought sofas and comfortable chairs, turning the library into a safe public space, for everyone.
In doing so, I realized that the library isn’t just a place to do research. They are, in fact, places that offer an opportunity to connect with the past, present and future. All that is required is a tiny bit of curiosity. Libraries are places that should be full of life. They help us adjust to the world, and their doors must be kept open to everyone for free!
1.What inspired the author to set up a library for students?
A.Some well-known classics.
B.His early experience of reading.
C.The suggestion of a librarian.
D.The book: Little House in the Big Woods.
2.When did the author begin to build his own library?
A.In primary school. B.In high school.
C.During university years. D.After leaving college.
3.What does the author intend to tell us in paragraph 4?
A.What his career was like.
B.Where he stored his books.
C.Why school kids loved reading.
D.How he improved the school library.
4.Which of the following is the best title for the text?
A.A private library B.Read with curiosity
C.A librarian’s life D.More than just books
Two European Summer Must “Seas”
When you think of summer, the beach, clear water, sunny skies, and relaxing days are a few things that come to mind, and two of the best places to experience these summer feels are two gorgeous European bodies of water: the Mediterranean Sea and the Adriatic Sea! These two incredible Seas hold some of my favorite travel memories, and I would revisit each one in a heartbeat!
The Mediterranean Sea
The Mediterranean Sea can be accessed from various European countries as well as a few North African countries. And while many think of visiting Ibiza, Malta, or the Greek islands to experience the Mediterranean, my Mediterranean beach days came while visiting the seaside city of Marseille in the South of France! Marseille was a lovely city with easy access to the Sea, also with pretty sandy beaches. The gorgeous crystal clear blue water made it unlike any beach day in America! Not only were the beaches amazing, but the city of Marseille was adorable and filled with numerous cute shops and seaside restaurants. And the Mediterraneanstyle food was delicious!
The Adriatic Sea
The Adriatic Sea is equally as stunning and surely worth a visit! The Croatian coast has numerous beach clubs, some private and some public, that tourists are able to visit and you can experience the beauty of the Adriatic Sea there! Zrce Novalja, a Croatian seaside town I visited, was impressively featured by the rather rocky beach in place of sand. The rocks were small and smooth, making swimming in the sea and wading in the water just as easy as sandy beaches! Plus, the locals in Croatia are also extremely friendly, making the experience even more memorable.
1.The writer's trip to the two seas was full of ________.
A.unbearable hardships B.various adventures
C.wonderful experiences D.funny events
2.From which place did the writer get to the Mediterranean Sea?
A.Ibiza. B.Malta.
C.The Greek islands. D.Marseille.
3.What makes Zrce Novalja so special?
A.Its beach clubs. B.Its beautiful sea.
C.Its rocky beach. D.Its friendly locals.
Almost everyone around us uses a phone. Phones provide a simple and efficient way to conduct work or _______ with social arrangements from day to day. Several times in the course of a work day, you may be _______ by your workmates, students or friends by means of phone. If you want a/an _______ with your department head, you will _______ call him and arrange a time with him. If you are unable to _______ your appointment, or if you find you have to be _______ for it, you will phone and change the _______. In this way, no one _______ time waiting for someone who is not coming. If you want to buy something, you will “let your _______ do the walking”. That is, you call ahead to make sure the store has what you ________. If it is an expensive item, you might call several stores to ________ prices so that you can buy the cheapest one. If you want to __________ a train or plane, after finding out the prices, you can call to __________ the ticket; if you want to shop for clothes after work, you might call to ask how __________ the store is open before you travel all the way there.
Phones are easily __________. In streets, you can see public phones in which you feed coins to make a call. Phones have __________ answering services; if you are not at home or in the office, or don’t wish to be __________, you switch on a machine, which will answer the call for you. A pre-recorded message will say to the __________, “I’m sorry, I’m not available at the moment. Please leave your name and number and I will call you __________ as soon as possible.” It’s more efficient to __________ one’s name and number than to waste their time calling again and again.
1.A.deal B.communicate C.share D.talk
2.A.suggested B.reminded C.connected D.ignored
3.A.prize B.promise C.deal D.appointment
4.A.never B.usually C.seldom D.frequently
5.A.keep B.make C.break D.take
6.A.intended B.prepared C.late D.ready
7.A.mind B.place C.plan D.idea
8.A.arranges B.takes C.kills D.wastes
9.A.feet B.finger C.head D.legs
10.A.need B.hate C.have D.think
11.A.pay B.cut C.raise D.compare
12.A.make B.take C.miss D.get
13.A.choose B.offer C.book D.ask
14.A.late B.fast C.soon D.early
15.A.suitable B.usable C.enjoyable D.available
16.A.proper B.automatic C.artificial D.free
17.A.noticed B.upset C.disturbed D.worried
18.A.seller B.visitor C.speaker D.caller
19.A.on B.back C.up D.at
20.A.leave B.sign C.remember D.write
假定你是李华, 在疫情期间，你所在社区招募英语自愿者，向外籍人士宣传疫情防控。请你写信应聘，内容包括：
1. 写信目的；
2. 个人优势；
3. 表达期待。
注意：1. 词数100左右；
2. 可适当增加细节，以使行文连贯。
3. 参考词汇：疫情防控 epidemic prevention and control; 冠状肺炎 COVID-19
Dear Sir/ Madam,
__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Yours,
Li Hua
