单选题Twenty dollars ______ obviously too much to pay for such a small item. A. were B. are C. is D. have been

单选题 In everyday usage "hot" means "having a lot of heat". Many people think that "cold" is something completely separated from heat. But this is not true. "Cold" simply means "having little heat". Your life depends on heat. In fact, every living thing depends on it. Without heat, every living thing would be frozen to death. All living things get their heat from the sun, which provides the conditions in which life is possible. Since before the dawn of history, man has been able to make his own heat. He has been able to release the sun's heat that is trapped in things such as wood, coal, and oil. And he has been able to use this heat. Heat has made civilization possible. With heat, man could melt metals. As man learned to use metals and fuels, industries grew. As a result, engines were invented. These are machines that change heat energy into mechanical energy. Engine can do the work of many men. Without engines industrial civilization is impossible. Yet when the first engines were built in the 17th century, men were still wondering about the nature of heat. "What is it?" they asked. Not until the early years of the 19th century did they find the right answer.

单选题I hadn't seen him for years, but I ______ his voice on the telephone. A. realized B. discovered C. recognized D. heard

单选题Peter misunderstood the instructions his boss gave him and mailed the wrong documents to the supplier.

单选题Sending e-mail is relatively cheap and quick. For example, a short message can be sent around the world in less than a minute. When you send an e-mail, the message waits in the person's mailbox which is located on the service provider' s server. The message waits there until the person cheeks his or her mailbox and downloads the message from the server to his or her computer.

单选题Don't speak at the same time. ______ please. A) One at a time C) On by one time B) One for each time D) Each at a time

单选题Advertising is different from other forms of communication __________ the advertisers pay for the message to be delivered.

单选题Most pupils in China are too shy to speak ______. A. in public B. in the public C. in a public D. at public

单选题However, so long as man has good health, he can enjoy the pleasures of human life.

单选题These programs are important to business success and will also contribute to the community at large.

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单选题She closed her eyes and sat there still as if she ______ asleep. A. was B. were C. had been D. have been

单选题The electronic shaver ______ before it can be used.

单选题Try hard as he will，he never seems able to do the work satisfactorily． A．他是愿意努力工作，但他却从来都不满意工作。 B．尽管他是愿意努力工作，但是他好像从来都不能使他的工作令人满意。 C．他愿意努力工作，也好像从来都不能使他的工作令人满意。 D．像他希望的那样尽心尽力，不过他好像从未对他的工作满意过。

单选题Being engaged in the research work, Dr. Yang seldom goes anywhere ______ his office.

单选题[此试题无题干]

单选题According to the passage, it is very unlikely that an American hospital is owned by ______.

单选题Tom found ______ very hard to get high marks.

单选题Each educational system is not perfect in a strict sense, which has its______.