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.
B
Aging brings wrinkles, sagging bodies and frustrating forgetfulness. But getting older is not all bad for many people. Mounting evidence suggests aging may be a key to happiness. There is conflicting research on the subject, however, and experts say it may all boil down to this: Attitude is everything.
Older adults tend to be more optimistic and have a more positive outlook on life than their younger and stressed opposites. The big question is why seniors are happier. A recent study suggests one reason: Older adults remember the past through happy memories. Aging can bring more cheer as people become more comfortable with themselves and their roles in society. The older adults said they were enjoying more time with their family, spending more time on hobbies and having greater financial security and did not have to work.
But others are doubtful about the link between happiness and growing older.
"The notion that those in old age are happiest is misleading," said Richard Easterlin, a professor of economics at the University of Southern California. "It is based on comparing people of different ages who are the same in terms of income, health, family life." Easterlin added, "When you take account of the fact that older people have lower income than younger, are less healthy, and more likely to be living alone, then you will find it hard to accept that they are happier.
In fact, scientists have found that as people age, their health declines and social networks disappear as their friends die, which can make the elderly less happy.
Even if one does give in to age's dark side, health and happiness don't always go hand-in-hand. It's all about attitude. Research by the University of Chicago’s Yang suggests that attitude about life and happiness, is partly shaped by the era in which a person was born. It turns out that individuals who adapt the best to changes also have the highest expected levels of happiness.
Despite the conflicting findings about aging and happiness, the good news is that there doesn’t appear to be a limit to how much happiness one can achieve in one’s life. “Most people desire happiness,” Easterlin said. “To my knowledge, no one has identified a limit to attainable happiness.”
1.What does the last paragraph mainly tell us?
A.The key factor to older adults’ happiness
B.There is a conflict between aging and happiness
C.No one can define the limit to happiness.
D.The relationship between health and happiness.
2.Why are some seniors happier according to some experts?
A.They focus on what makes them feel good.
B.They have their own circle of friends.
C.They have better income after retirement.
D.They can enjoy social welfare services.
3.What can we learn from the passage?
A.People of the same age have the same sense of happiness.
B.Attitude may play a very important role in happiness.
C.People who adapt the best to changes are more likely to be unhappy.
D.Older adults who have more valuable life experience are more optimistic.
4.What’s the topic discussed in the passage?
A.Whether aging or attitude brings happiness.
B.Why seniors adapt the best to changes in society.
C.What the limit to an elder person’s happiness is.
D.How older people feel compared with younger people.
Born blind is tough in any case. But things were even harder for Srikanth Bolla who was born in a small village in India, where the common belief was that kids with disabilities were “of no use” and therefore, better off dead. Fortunately, Srikanth’s parents loved their son and refused to give him up. Instead, they encouraged the blind boy to dream big and reach for the star.
Srikanth did not disappoint his parents. The now twenty-four-year-old is the founder CEO of Bollant Industries.
Of course, getting here was not easy. Being both blind and poor meant that Srikanth had to face hard challenges. As a young boy, Srikanth attended a regular school near his home. Unfortunately, the students and teachers didn’t quite like him because of his disability. As a result, the young boy was largely ignored and often spent the entire day alone.
Concerned this would hold back Srikanth’ s development, his family decided to send him to a special school in Hyderabad. Sure enough, the young boy soon rose to the top of his class, earning awards in speech and debate competitions. But Srikanth was prevented from studying sciences when he reached 10th grade, because it was thought too “dangerous” for a blind student. Not wanting to give up, Srikanth took legal action and became the first blind student in the country allowed to study sciences.
Late, after graduating from the Massachusetts Institute of Technology, Srikanth set up Bollant Industries in 2012.For just four years, it has become a powerhouse with over 450 employees,70% of whom are physically challenged.
Being disabled doesn’ t mean being unable. “If the world looks at me and says, ‘Srikanth, you can do nothing,’ I will look back at the world and say I can do anything.” the young man says.
1.Why was Srikanth sent to a special school?
A.His parents became richer than before.
B.He could be treated equally there.
C.This school was free for disabled students.
D.He was sent away by the regular school.
2.What can we know about Srikanth from the text?
A.He was born in a poor village.
B.He cared about disabled people.
C.His parents were strict with him in his study.
D.He was loved by the villagers when he was young.
3.What words can best describe Srikanth?
A.Intelligent and determined.
B.Active and honest.
C.Patient and careful.
D.Kind but stubborn.
4.What can be the best title for the text?
A.Chances Are Everywhere
B.No Challenges, No Success
C.Big Dream Makes a Difference
D.Disability Doesn’t Mean Being Unable
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.
假如你是李华，你的外国朋友Mr. Smith想要了解中国春节，请用英文写一篇介绍中国春节的短文。内容包括:
1. 春节的时间;
2. 庆祝春节的方式;
3. 春节的习俗。
注意:
1. 词数100左右
2. 可以适当增加细节，以使行文连贯
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短文改错
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。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(＼)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。
Two men were traveling together while a bear suddenly met them. One of them climbed up into the tree. The other, seeing that he must be attacked, immediate lay on his back on the ground. When the bear came up, feeling him with his nose and smelt him all over, he held breath. The bear soon left him, for it’s said that a bear won’t touches a dead body. When he was gone, the other travelers went down from the tree. And he asked his friend that the bear had whispered to his ear. “He gave me a piece of advice,” his companion replied. “Never to travel with a friend who deserts you in the face of danger.”
1.2.3.4.5.
6.7.8.9.10.
