2020届高考英语考前拔高每日练 综合训练（3）
1、We went through a period ______communications were very difficult in the rural areas.
A. which B. whose with which
2、Since I have little work experience, I will have to take a series of unpaid internships ________ I could find my ideal job. A.before
B.after
C.as
D.when
C. in which D.
3、He asked, \ →He asked me _________.
A.If I was a Party member or a League member B.am I a Party member or a League member C.was I a Party member or a League member D.whether was I a Party member or a League member
4、People have been wondering why elephants do not develop cancer even though they have lifespans(寿命)that are similar to humans, living 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. D.Sensitivity to DNA damage.
C.Cells killing themselves.
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.
5、The bad health effects of sleep loss during the week can’t be repaid by longer weekend sleep, according to a new study. Researchers have long known that sleep deprivation (剥夺) can cause weight gain and increase other health risks. But for those who force themselves out of bed every weekday after too few hours of shut-eye. They hope turning off the alarm on Saturday and Sunday will repay the weekly sleep debt and remove any ill effects.
The research, published in Current Biology, crushes those hopes. Despite complete freedom to sleep during a weekend recovery period,people in a sleep lab who were limited to five hours of sleep on weekdays gained nearly three pounds over two weeks and experienced disorders that would increase their risk for diabetes over the long term. While weekend recovery sleep had some benefits after a single week of sleep loss,those gains were wiped out when people fell right back into their same sleep-deprived schedule the next Monday.
“If there are benefits of catch-up sleep,they’re gone when you go back to your daily schedule. It’s very short lived,” said Kenneth Wright, director of the sleep and chronobiology lab at the University of Colorado at boulder.“These health effects are long-term. It’s kind of like smoking once was—people would smoke and wouldn’t see an immediate effect on their health, but people will say now that smoking is not a healthy lifestyle choice. I think sleep is in the early stage of where smoking used to be.
Wright said that the study suggests people should put sleep in the first place—cutting out the “sleep stealers” such as watching television shows or spending time on their phones. Even when people don’t have a choice about losing sleep because of child-care responsibilities or job schedules, they should think about getting sleep in the same way they would get a healthy diet or exercise.
1.What do the researchers find about weekend recovery sleep? A.It is common among people. B.It will make people healthier. C.It can make people put on weight. D.It s able to make up for the sleep loss.
2.What does the underlined word “crushes” mean? A.Arouses. C.Deepens.
B.Guarantees. D. Ruins.
2020届高考英语考前拔高每日练 第3练
