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 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, recently the size and thickness of a penny, intended to power various micro/nano-electromechanical systems (M/NEWS). 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 (晶格结构) 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 the battery could be thinner than the thickness of human hair.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. |
Jae Kwon gave examples in Paragraph 4 ________.
| A.to show chemical batteries are widely applied |
| B.to indicate nuclear batteries can be safely used |
| C.to describe a nuclear-powered system |
| D.to introduce various energy sources. |
Liquid semiconductor is used to ________ .
| 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 |
According to Jae Kwon, his nuclear battery ________.
| A.uses a solid semiconductor | B.will soon replace the present ones |
| C.could be extremely thin | D.has passed the final test |
The text is most probably a ________.
| A.science news report | B.book review |
| C.newspaper ad | D.science fiction story |
All over the world people enjoy sports. Sports help to keep people healthy, happy and help them to live longer.
Sports change with the season. People play different games in winter and summer.
Games and sports often grow out of people’s work and everyday activities. The Arabs use horses or camels in much of their everyday life; they use them in their sports, too.
Some sports are so interesting that people everywhere go in for them. Football, for example, has spread around the world. Swimming is popular in all countries near the sea or in those with many rivers.
Some sports or games go back to thousands of years, like running or jumping. Chinese boxing, for example, has a very long history. But basketball and volleyball are rather new. Neither one is a hundred years old yet. People are inventing new sports or games all the time.
People from different countries may not be able to understand each other, but after a game they often become good friends. Sports help to train a person’s character(性格). One learns to fight hard but fight fair, to win without pride and to lose with grace(体面)According to this passage we know that _____.
| A.people began to play about one hundred years ago |
| B.about 100 years ago people ran or jumped when they played |
| C.basketball has a longer history than volleyball |
| D.not all the games have a long history |
The writer didn’t tell us in this passage that _____.
| A.basketball was invented in America |
| B.sports change with the season |
| C.games and sports often grow out of people’s work and everyday activities |
| D.football is played all over the world |
People all over the world enjoy sports because _____.
| A.sports are interesting |
| B.sports help to keep people healthy , happy and to live longer |
| C.sports help to train one’s character |
| D.all of the above |
From this passage we can see that_____.
| A.sports and games are unimportant things that people do |
| B.sports and games should be treated(对待)only as amusement(娱乐活动) |
| C.sports and games are only useful to the old |
| D.sports and games can help people understand each other. |
Dr. Martinez put on a false smile (假笑) as she entered Janet Eslin’s hospital room. She couldn’t let Janet see that she was worried. Yet she had been searching for the cause of Janet’s illness and hadn’t found a clue(线索).
“How are you feeling today?” Dr. Martinez asked her patient. Janet replied that she felt about the same----terribly uncomfortable.
The doctor tried to get Janet’s mind off her health by talking about Janet’s vacation at Lake Winnow. But Dr. Martinez couldn’t keep her own mind on the conversation. She kept wondering what could be wrong with her patient.
Suddenly Janet’s words interrupted Dr. Martinez’s thoughts: “… the vacation was really perfect, except for the food. The last meal I ate was especially terrible.”
Dr. Martinez quickly snapped back into the conversation, “Janet, when did you eat that meal?” Janet said that it had been the day before yesterday.
“I think we’ve discovered your problem,” Dr. Martinez said as she left. Several hours later, Dr. Martinez was back with the answer. “Janet, the food you ate made you ill. You’re suffering from food poisoning. Now that we know what’s wrong, we can take care of your problem.”What made Janet sick?
| A.an insect bite | B.bad food |
| C.bad water | D.cold weather |
What is the main idea of the story?
A doctor discovers what made Janet sick.
Dr. Martinez becomes ill.
Janet goes on vacation.
A doctor talks to Janet in the hospital.Where did Janet go on her vacation?
A. She took a trip to the city.
B. She went camping in the mountains.
C. She spent a week at the seashore.
She took a trip to a lake.What does the underlined word “interrupted” mean?
| A.talked about |
| B.told over again |
| C.broke in while someone was talking |
| D.never stopped listening to the other person |
When someone says “well, I guess I’ll have to face the music”, it doesn’t mean that he is planning to go to hear a singer. It is something far less happy, as you are called in by your leader to explain why you did this and did that or why you did not do this or that.
At some time or another, every one of us has to “face the music”, especially as children. We can all remember father’s angry word “I wasn’t to talk to you” and only because we did not listen to him. What a bad thing it was !
In the middle or at the end of every term, we students have to “face the music”. The result of the exam will decide whether we will face the music or not. If …that means parents’ cold faces and the contempt of the teachers and classmates.
“To face the music” is well known to every American, younger or old. It is at least 100 years old. It really means that you have to do something, no matter how terrible the whole thing might be, because you know you have no choice. “To face the music” means “to ____________”
| A.do something we don’t like to | B.go to the theater |
| C.go to the music show | D.do something that we want to |
If you didn’t listen to your father’s words, you would “face the music” ,or ____________.
| A.do something to please him | B.do something to make him angry |
| C.be punished by him | D.be pleased with him |
Before the exam, we’ll have to “face the music”. That’s why ____________.
| A.we like to take the exam | B.we are afraid of taking the exam |
| C.the exam is very important | D.we are afraid to pass the exam |
In the third paragraph. “If...” really means “If _______________”.
| A.we got a “D” in the exam |
| B.we got an “A” in the exam |
| C.the exam is easy |
| D.the exam is difficult |
| For Children Museum: Children’s Museum, Sundays, 89 North Street, 67641235 Story time: Children’s Library, 106 Green Street, Wednesdays during 9:30 a.m -5:00p.m. 66599624 Sports: Soccer Club, Tuesdays and Thursdays, 16 Yangtze Road, 96725643 Basketball Club, Wednesdays and Fridays, 79071632 Cinema: New films for children, 99 Brick Road, 69001354 |
| Useful Phone Numbers Fast Food Restaurant: 66387901 Hospital: 68787451 Visitor Information Center: 800-120-9847 Taxi: 79210583 Visitor Hotel Information: 800-739-7302 |
It’s Friday afternoon,you can go to_______ .
| A.visit the museum | B.play soccer |
| C.play basketball | D.read children’s stories |
If children want to watch new films,they should go to________.
| A.16 Yangtze Road | B.89 North Main Street |
| C.106 Green Street | D.99 Brick Road |
If you dial (拨号)66387901,you can __________.
| A.ask for some hotel information | B.do some shopping |
| C.have a good story time | D.order fast food in a restaurant |
Lily’s father is ill.She should dial________.
| A.800-120-9847 | B.79210583 | C.6878745 l | D.96725643 |
Although English is not as old as Chinese, it is spoken by many people around the world every day. English speakers are always creating new words, and we should be able to know where most words come from.
Sometimes, however, no one may know really where a word comes from. Did you ever think about why hamburgers are called hamburgers, especially when they are not made with ham( 火腿 )? About a hundred years ago, some men went to America from Europe. They came from a big city in Germany called Hamburger. They didn’t speak good English, but they ate good food. When some Americans saw them eating round pieces of beef, they asked the Germans what it was. The Germans did not understand the question and answered. “We came from Hamburger.” One of these Americans owned a restaurant, and had an idea. He cooked some round pieces of beef like what the men from Hamburger ate. Then he put them between two pieces of bread and started selling them. Today “ hamburgers” are sold in many countries around the world.
Whether this story is true or not, it certainly is interesting. Knowing why any word has a certain meaning is interesting, too. The reason may be found in any large English dictionary.According to the writer, English ______.
| A.is as old as Chinese | B.is not so old as Chinese |
| C.is older than German | D.is very difficult to learn |
According to the story,_______.
| A.few Americans like hamburgers |
| B.hamburgers are made with beef |
| C.hamburgers are made with ham |
| D.hamburgers were sold all over the world about a century ago |
According to the writer, which of the following can be found in any large English dictionary?
| A.Where all the new words come from |
| B.Where those Germans came from |
| C.The reason why any word has a certain meaning. |
| D.The reason why English is spoken around the world |
According to the story, the word “hamburger” comes from ________.
| A.China because it has a long history |
| B.England because Germans don’t speak good English |
| C.the round pieces of beef those people from Hamburger brought to America |
| D.English speakers because they always create new words |