Scientists have developed a new cancer drug. So far, they have tested it only in laboratory
animals. The drug is designed to enter and kill cancer cells, but not healthy cells.First, the drug
enters the cancer cells and stops their supply of blood. Then it releases poison to destroy the
cancer cells.
Researchers at the Massachusetts Institute of Technology(MIT) in Cambridge carried
out the study. The results appeared in Nature magazine. A school report called the drug an
"anticancer smart bomb".
Ram Sasisekharan is a professor at MIT. He says that his team had to solve three problems.
They had to find a way to destroy the blood vessels, then to prevent the growth of new ones.
But they also needed the blood vessels to supply chemicals to _________.
So, the researchers designed a two-part "nanocell". The cell is measured in nanometers(毫微米),
or one thousand millionth of a meter.
The scientists say thay that it was small enough to pass through the blood vessels of the cancer,
but it was too big to enter normal blood vessels. The surface of the nanocells also helped them to
avoid natural defenses.
The scientists designed the cell as a balloon inside a balloon. They filled the outer part with a
drug that caused the blood vessels to die. That cut off the blood supply and put the nanocells inside
the cancer. Then, the nanocells slowly released drugs to kill the cancer cells.
The team says that the treatment killed the cancer and avoided healthy cells better than other
treatments. Untreated mice with cancer survived for twenty days. The scientists say that mice with
the best current treatments lived for thirty days. In this study, they say that eighty percent of the mice
treated with the nanocells lived more than sixty-five days.
The scientists say that more studies are needed before the new drug can be tested in humans.
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5. Please translate the underlined sentence in the eighth paragraph into Chinese
________________________________________________________________________
2. So far , they have tested it only in laboratory animals.
3. destroy the cancer
4. It can be cured in the future, people can succeed in testing the drug in animals, and also succeed in testing it in humans.
5 .研究小组说,这种治疗方法与其它方法相比,可以更好地***死癌细胞,并避免健康细胞受损.
答案不唯一。
Third, note-taking offers variety to your study time and helps you to hold your interest.
You will want to take notes during classroom discussions and while reading a textbook or doing
research for a report. 2._____ whenever or however you take notes, keep in mind that note-taking is
a selective process. 3._____
The following methods may work best for you.
Read the text quickly to find the main facts and ideas in it.
Carefully read the text and watch for words that can show main points and supporting facts.
Write your notes in your own words.
4.____
Note any questions or ideas you may have about what was said or written.
As you take notes, you may want to use your own shorthand (速记). When you do, be sure that you
understand your symbols and that you use them all the time. 5._____
B. There are three practical note-taking methods.
C. You must write your notes on separate paper.
D. Otherwise, you may not be able to read your notes later.
E. You will also want to develop your own method for taking notes.
F. That means you must first decide what is important enough to include in your notes.
G. First, the simple act of writing something down makes it easier for you to understand and remember it.
subway trains. and some do one simple job. When an automatic washing machine is switched on,
water pours in. The machine waits until the water is warm enough for washing clothes. It does this by
"feedback"(反馈). Information about what is happening is feedback into the robot to tell what to do
next. Our eyes, ears and other senses are our feedback. They tell us what is going on around us. So
robots are like human beings in two ways. They work and they have feedback.
In some ways robots are better than human beings. They work quickly and do not make mistakes.
They do not get bored doing the same job over and over again. And they never get tired. So robots are
very useful in factories. They can be taught to do many different jobs. First their electronic brain must be
shown how the job is done. A person moves the robot"s "arms" and "hands" through each part of the job.
The most intelligent robots can move and see. Their eyes are cameras. Their fingers can feel shapes
and sizes of the objects. These robots have computer brains linked to their eyes and fingers, which
control their actions. The expensive robots are used in scientific research. They do such job as handling
radioactive materials.
B. there are various kinds of robots
C. we see robots only at certain times
D. robots can be easily controlled
B. They will probably take over in the future.
C. They are very helpful and useful to humans.
D. They are machines that break down a lot.
B. robots can do many jobs
C. robots only get in the way
D. robots sometimes cause troubles
B. it can do boring jobs for people
C. it will never bore people
D. it will work much better than human beings
![](http://img.shitiku.com.cn/uploads/allimg/20191212/20191212132120-12156.png)
B. are very cheap
C. are very big
D. are very costly
getting a college degree, new studies suggest in the latest effort to examine the effects of television
on children.
One of the studies looked at nearly 400 northern California third-graders.Those with TVs in
their bedrooms scored about eight points lower on math and language arts tests than children
without bedroom TVs.
A second study, looking at nearly 1000 grown-ups in New Zealand,found lower education
levels among 26-year-olds who had watched lots of TV during childhood.But the results don"t
prove that TV is the cause and don"t rule out(排除) that already poorly motivated(有动机的)
youngsters may watch lots of TV.
Their study measured the TV habits of 26-year-olds between ages 5 and 15. Those with
college degrees had watched an average of less than two hours of TV per weeknight during
childhood, compared with an average of more than 2.5 hours for those who had no education
beyond high schools.
In the California study, children with TVs in their rooms but no computer at home scored the
lowest, while those with no bedroom TV but who had home computers scored the highest.
While this study does not prove that bedroom TV sets caused the lower scores,it adds to
accumulating(增加) findings that children shouldn"t have TVs in their bedrooms.
B. not be interested in math
C. be unable to go to college
D. have had computers in their bedrooms
B. Habits of TV watching reduce learning interest.
C. TV watching leads to lower education levels of the 15-year-olds.
D. The connection between TV and education levels is difficult to explain.
B. Children should be forbidden from watching TV.
C. TV sets shouldn"t be allowed in children"s bedrooms.
D. Further studies on high-achieving students should be done.
learning. One needs memory to ride a bicycle. A dog needs to remember if it is to come when called.
Memory is said to be stored in the brain as a "memory trace(记忆痕)." What makes up this trace
is not known. Some scientists believe that certain chemical substances may carry certain memories.
For example, one substance, when given to rats, causes them to fear the dark.
Other research into memory has to do with how the brain works. Psychologists use three means
to find out how a person remembers. For example, give a person a grocery list. Let the person
memorize the list, then put it away. The most natural way to find out how much a person remembers
of the grocery list is to ask what he or she remembers. This is called the method of recall. Another
method is called recognition. Give the person another grocery list. Ask him or her to choose items on
the first list from the items that are on only the second list. Often a person will be able to recognize
things that he or she cannot recall. A third method of finding how much a person remembers is called
relearning. Here the person is asked to read over the first list. The person will probably learn the list
the second time faster than he did the first time. The difference in the time it takes to relearn the list is
thought of as a measure of how much a person has remembered.
One way of remembering something is to repeat it many times. Interest is very important. Boring
lists of facts are much more difficult to remember than something that we understand and are interested
in. Motivation, or wanting to do something, is also important. Motivation is linked with reward. For
example, a hungry animal quickly learns how to do something if that action gets the animal food. In
humans, wanting to learn is often motivation. The praise of a teacher or the knowledge that an answer
is correct is rewarding.
B. it is hard to tell what a memory trace consists of
C. chemical substances carry certain memories
D. memory is stored in the brain as a substance
B. recall
C. memorization
D. relearning
B. The type of list items.
C. The time difference of relearning.
D. The time difference of brain working.
B. praise it in words
C. reward it with food
D. weaken its motivation
treat sticks as dolls, carrying them around until they have children of their own. Young males engage
in such behavior much less frequently.
The new work by Sonya M. Kahlenberg and Richard W. Wrangham, described this week in the
journal Current Biology, provides the first evidence of a wild nonhuman species playing with dolls, as
well as the first known sex difference in a wild animal"s choice of playthings.
The two researchers say their work adds to a growing body of evidence that human children are
probably born with their own ideas of how they want to behave, rather than simply mirroring other
girls who play with dolls and boys who play with trucks. Doll play among humans could have its
origins in object-carrying by earlier apes (猿类), they say, suggesting that toy selection is probably
not due entirely to socialization.
"In humans, there are obvious sex differences in children"s toy play, and these are remarkably
similar across cultures," says Kahlenberg. "While socialization by elders and peers has been the
primary explanation, our work suggests that biology may also have an important role to play in activity
preferences."
In 14 years of data on chimpanzee behavior at the Kibale National Park in Uganda, Kahlenberg
and Wrangham counted more than 100 examples of stickcarrying. Some young chimpanzees carried
sticks into the nest to sleep with them and on one occasion built a separate nest for the stick. "We
have seen juveniles occasionally carrying sticks for many years, and because they sometimes treated
them rather like dolls, we wanted to know if in general this behavior tended to represent something
like playing with dolls," says Wrangham, a Professor at Harvard. "If the doll hypothesis (假设)
was right, we thought that females should carry sticks more than males do, and that the chimpanzees
should stop carrying sticks when they had their first child. We have now watched enough young
chimpanzees to prove both points."
B. She treats them as dolls.
C. She makes useful tools from them.
D. She treats them as weapons.
B. Socialization.
C. Environment.
D. Cultural difference.
B. sex difference is the only factor in human"s choice of playthings
C. the biology factor may also influence toy choice
D. people choose different toys in different cultures
B. different factors cause humans and chimpanzees to choose different playthings
C. only female chimpanzees have playthings
D. chimpanzees usually choose playthings for their children
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