单选题 If this technique should be extended to other crop plants, the rate of production ______ in this area.

单选题In order to help the students get a better understanding of the new conception, the professor ______ it with many examples.

单选题Billy, a hard-working student, is fourteen years old and in the ninth grade. He has a part-time job that (21) him up every morning at five o' clock, when most people are still (22) asleep. He is a newspaper boy. Each morning, Billy leaves the house at 5:15 to go to the (23) where the newspapers always are. The newspapers were (24) to the comer by truck at midnight. He always takes a wagon to (25) them. In the winter it is still dark (26) he gets up every day, but during the rest of the year it is (27) . Billy' must send the newspapers to the houses of people on his (28) in all kinds of weather. He tries to put each paper on the po ch(门廊)where it will be (29) from wind and rain or snow. Sometimes his customers give him tips, (30) him very excited. Billy earns about$70 per month through hard (31) , and he is saving some of the money to go to (32) , where he has always been longing to go. Besides that, he (33) the rest of the earnings on records and clothes. Once a month, he has to collect the (34) at night since many of them work during the day. That is when he is (35) so that he is full of excitement. Luckily, he gets greatly supported by his family. Billy has seventy customers now, but he doesn' t feel happy about the number. He dreams that he will get as many customers as possible some day. If that, he might win a prize for being an outstanding newspaper boy. He wants to win a trip to Europe, but he will be happy if he wins a new bicycle.

单选题How many significant demographic changes ever occurred in the past one million years?

单选题Only (within) the past 200 years (scientists have) found (out what) fire (is).

单选题Tom: Shall we try Pizza Hut tonight?Rachel: Sure. ______

单选题 Man still has a lot to learn about the most powerful and complex part of his body—the brain. In ancient times men did not think that the brain was the center of mental activity. Aristotle, the philosopher of ancient Greece, thought that the mind was based in the heart. It was not until the 18th century that man realized that the whole of the brain was involved in the workings of the mind. During the 19th century scientists found that when certain parts of the brain were damaged, men lost the ability to do certain things. And so, people thought that each part of the brain controlled a different activity. But modern research has found that this is not so. It is not easy to say exactly what each part of the brain does. In the past 50 years there has been a great increase in the amount of research being done on the brain. Chemists and biologists have found that the way the brain works is far more complicated than they had thought. In fact many people believe that we are only now really starting to learn the truth about how the human brain works. The more scientists find out, the more questions they are unable to answer. For instance, chemists have found that over 100,000 chemical reactions take place in the brain every second. Mathematicians who have tried to use computers to copy the way the brain works have found that even using the latest electronic equipment they would have to build a computer which weighed over 10,000 kilos. Some recent research also suggests that we remember everything that happens to us. We may not be able to recall this information, but it is all stored in our brains. Scientists hope that if we can discover how the brain works, the better use we will be able to put it to. For example, how do we learn language? Some children learn to speak, read and write when they are very young compared to average children. But scientists are not sure why this happens. They are trying to find out whether there is something about the way we teach language to children which in fact prevents children from learning sooner.

单选题Please ______ if you ever come to Sydney.

单选题Chemisty is closely ______ with other studies: physics, biology and so on.

单选题He had a clear ______of what was wrong with the machine and fixed it in a short time.

单选题To give praise ______ the giver nothing but a moment's thought and a moment's effort. A. costs B. tells C. benefits D. prizes

单选题Exposure to asbestos fibres can cause cancer ______.

单选题--Have you seen him recently? --Yes. I met him at ______ this morning. ( )

单选题John and I ______friends for eight years. We first got to know each other at a Christmas party. But we ______each other a couple of times before that.

单选题Like any teenagers, the face of One Teen Story is changing fast. Just a year old,the monthlymagazine of short fiction for young people is getting a new editor-in-chief: Patrick Ryan ,47, the asso-ciat

单选题Thatched houses are still preferred because of______.

单选题Several (people) in the crowd seemed (as) they were fighting (for) a (ticket).A. peopleB. asC. forD. ticket