题目内容
Not only my mother but also Aunt Mary and her family ______ happy with the prize.
A. were
B. has been
C. was
D. had been
| A |
| not only … but also连接两个主语时，谓语动词应和but also后面的主语Aunt Mary and her family保持一致，因此谓语动词应用复数形式。 |
每日10分钟口算心算速算天天练系列答案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/nanoelectromechanreal 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】Which of the following is true of Jae Kwon?
| A．He teaches chemistry at MU. |
| B．He developed a chemical battery. |
| C．He is working on a nuclear energy source. |
| D．He made a breakthrough in computer engineering. |
| 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．get rid of the radioactive waste | B．test the power of nuclear batteries. |
| C．decrease the size of nuclear batteries | D．reduce the damage to lattice structure. |
| 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 story |