题目内容
________，he has much experience in learning English．
- A.As is he young
- B.Young as he is
- C.As young he is
- D.Young although he
口算题天天练系列答案Batteries can power anything from small sensors to large systems．While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves．University of Missouri（MU） researchers are developing a nuclear energy source that is smaller, lighter and more efficient．
“To provide enough power, we need certain methods with high energy density（密度）”，said Jae Kwon, assistant professor of electrical and computer engineering at MU．“The radioisotope（放射性同位素） battery can provide power density that is much higher than chemical batteries．”
Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro / nanoelectromechanical systems （M/NEMS）．Although nuclear batteries can cause concerns, Kwon said they are safe．
“People hear the word ‘nuclear’ and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems．”
His new idea is not only in the battery’s size, but also in its semiconductor（半导体）．Kwon’s battery uses a liquid semiconductor rather than a solid semiconductor．
“The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure（晶体结构） of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem．”
Together with J．David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery．In the future, they hope to increase the battery’s power, shrink its size and try with various other materials．Kwon said that battery could be thinner than the thickness of human hair．
【小题1】Jae Kwon gave examples in Paragraph 4_________．
| A．to show chemical batteries are widely applied． |
| B．to introduce nuclear batteries can be safely used． |
| C．to describe a nuclear-powered system． |
| D．to introduce various energy sources． |
| A．uses a solid semiconductor | B．will soon replace the present ones． |
| C．could be extremely thin | D．has passed the final test． |
| A．science news report | B．book review |
| C．newspaper ad | D．science fiction |
A four-year study of 200 college students found that those who drink heavily and started drinking at an early age demonstrate poor decision-making skills, just like long-term, chronic(长期的) alcoholics. Researchers at the University of Missouri-Columbia believe early onset binge drinking negatively affects psychological development.
The researches examined college students between the ages of 18 and 22. After three years, they tested them using the Iowa Gambling Test, which measures the tendency to make immediate (disadvantageous) or long-term (advantageous) choices.
Based on the students’ reported drinking habits, they were grouped into four categories: low binge drinkers, moderate binge drinkers, increasing binge drinkers and stable or high binge drinkers.
“Students in the stable or high alcohol use category, who had longer histories of binge drinking, made riskier and less advantageous choices, which reflect problems associated with planning for the future,” the researchers reported.
The study also found that only students who started binge drinking when they were younger showed impairment on the task.
“There is reason to think that heavy binge drinking during adolescence, when the brain is still rapidly developing, may have some negative legacy (遗传) on psychological development,” said Kenneth J. Sher of MU’s Midwest Alcoholism Research Center in a news release. “The interesting thing is that if we were to just look at binge drinkers and how impaired they are in the decision-making process as juniors, we’d really be obscuring(使模糊) the important issue, which is how long they’ve been binge drinkers and / or how early they started.”
【小题1】What does the passage mainly tell us?
| A．Four categories of heavy drinkers. |
| B．Heavy drinking affects college students. |
| C．Early onset binge drinkers are poor at decision-making. |
| D．People drinking at an early age will develop into binge drinkers. |
| A．Low binge drinkers | B．moderate binge drinkers |
| C．Increasing binge drinkers | D．Stable binge drinkers |
| A．adolescent students were not suitable for drinking |
| B．drinking too much will slow the growth of the brain |
| C．the brain has not fully developed during adolescence |
| D．drinking will make the students make dangerous choices |
| A．he is quite clear about what the important issue is |
| B．if binger drinkers started late, there would be no bad effect |
| C．the important issue is how impaired the students are in decision-making |
| D．only early binge drinkers will have their decision-making ability affected |