单选题The book, which is a useful guide for today's young people, deals with many questions and problems that {{U}}face{{/U}} them at school and at home as well as in society.

单选题Evidence collected by the spacecraft on Mars shows some present volcanic action, though the volcanoes are believed to be dormant if not dead.

单选题______does she do anything important without asking her parents'advice first. A．Usually B．Seldom C．Sometimes D．Often

单选题This sort of rude behavior in public hardly ______ a person in your position.

单选题Without electronic computers, much of today's advanced technology______achieveD．

单选题Our car trunk ______ with suitcases and we could hardly make room for anything.

单选题He meant telling us about it, but he forgot to tell us.

单选题Which of the following is an example of inertia?

单选题 Assuming that the engineering problems could be overcome, the production of a time machine could open up a Pandora's box of causal paradoxes. Consider, for example, the time traveler who visits the past and murders his mother when she was a young girl. How do we make sense of this? If the girl dies, she cannot become the time traveler's mother. But if the time traveler was never born, he could not go back and murder his mother. Paradoxes of this kind arise when the time traveler tries to change the past, which is obviously impossible. But that does not prevent someone from being a part of the past.Suppose the time traveler goes back and rescues a young girl from murder, and this girls grows up to become his mother. The causal loop is now self-consistent and no longer paradoxical. Causal consistency might impose restrictions on what a time traveler is able to do, but it does not rule out time travel per second. Even if time travel isn't strictly paradoxical, it is certainly {{U}}weird{{/U}}. Consider the time traveler who leaps ahead a year and reads about a new mathematical theorem in a future edition of Scientific American. He notes the details, returns to his own time and teaches the theorem to a student, who then writes it up for Scientific American. The article is, of course, the very one that the time traveler reads. The question then arises: Where did the information about the theorem come from? Not from the time traveler, because he read it, but not from the student either, who learned it from the time traveler. The information seemingly came into existence from nowhere, reasonlessly. The bizarre consequences of time travel have led some scientists to reject the notion outright. Stephen W. Hawking of the University of Cambridge has proposed a "{{U}}Chronology{{/U}} protection conjecture," which would outlaw causal loops. Because the theory of relativity is known to permit causal loops, chronology protection would require some other factors to intercede to prevent travel into the past. What might this factor be? One suggestion is that quantum processes will come to the rescue. The existence of a time machine would allow particles to loop into their own past. Calculations hint that the ensuring disturbance would become self-reinforcing, creating a runaway surge of energy that would wreck the wormhole.

单选题The use of the phrase "comes in handy" underlined in Paragraph 2 indicates that the process is ______

单选题The local residents were unhappy about the curfew in this region and decided to ______ it.

单选题 Electronic mail has become an extremely important and popular means of communication. The convenience and efficiency of electronic mail are threatened by the extremely rapid growth in the volume of unsolicited commercial electronic mail. Unsolicited commercial electronic mail is currently estimated to account for over half of all electronic mail traffic, up from an estimated 7 percent in 2001, and the volume continues to rise. Most of these messages are fraudulent or deceptive in one or more respects. The receipt of unsolicited commercial electronic mail may result in costs to recipients who cannot refuse to accept such mail and who incur costs for the storage of such mail, or for the time spent accessing, reviewing, and discarding such mail, or for both. The receipt of a large number of unwanted messages also decreases the convenience of electronic mail and creates a risk that wanted electronic mail messages, both commercial and noncommercial, will be lost, overlooked, or discarded amidst the larger volume of unwanted messages, thus reducing the reliability and usefulness of electronic mail to the recipient. Some commercial electronic mail contains material that many recipients may consider vulgar or pornographic in nature. The growth in unsolicited commercial electronic mail imposes significant monetary costs on providers of Internet access services, businesses, and educational and nonprofit institutions that carry and receive such mail, as there is a finite volume of mail that such providers, businesses, and institutions can handle without further investment in infrastructure. Many senders of unsolicited commercial electronic mail purposefully disguise the source of such mail. Many senders of unsolicited commercial electronic mail purposefully include misleading information in the messages' subject lines in order to induce the recipients to view the messages. While some senders of commercial electronic mail messages provide simple and reliable ways for recipients to reject (or 'opt-out' o0 receipt of commercial electronic mail from such senders in the future, other senders provide no such 'opt-out' mechanism, or refuse to honor the requests of recipients not to receive electronic mail from such senders in the future, or both. Many senders of bulk unsolicited commercial electronic mail use computer programs to gather large numbers of electronic mail addresses on an automated basis from Internet websites or online services where users must post their addresses in order to make full use of the website or service. The problems associated with the rapid growth and abuse of unsolicited commercial electronic mail cannot be solved by the government alone. The development and adoption of technological approaches and the pursuit of cooperative efforts with other countries will be necessary as well.

单选题With the joint effort of everyone, the plan is ______ to succeed; I'm sure of that.

单选题If you had done as I told you, this______. A．should have not happened B．would not have happened C．did not happen D．had not happened

单选题Most parents, I suppose, have had the experience of reading a bedtime story to their children. And they must have 41 how difficult it is to write a 42 children"s book. Either the author has aimed too 43 , so that the children can"t follow what is in his (or more often, her) story, 44 the story seems to be talking to the readers. The best children"s books are 45 very difficult nor very simple, and satisfy both the 46 who hears the story and the adult who 47 it. Unfortunately, there are in fact 48 books like this, 49 the problem of finding the right bedtime story is not 50 to solve. This may be why many of books regarded as 51 of children"s literature were in fact written for 52 . "Alice"s Adventure in Wonderland" is perhaps the most 53 of this. Children, left for themselves, often 54 the worst possible interest in literature. Just leave a child in bookshop or 55 and he will 56 willingly choose the books written in an imaginative way, or have a look at most children"s comics, full of the stories and jokes which are the 57 of teachers and right-thinking parents. Perhaps we parents should stop trying to brainwash children into 58 our taste in literature. After all children and adults are so 59 that we parents should not expect that they will enjoy the 60 books. So I suppose we"ll just have to compromise over that bedtime story.

单选题One person ________10 now goes to a university in this country.

单选题The very ubiquity of electronic communications can have a surprising downside, notes Richard Kohn, a military historian at the University of North Carolina: a wife becomes accustomed to frequent e-mail from her husband, until he can't get to a computer. And then her anxiety increases. A. failure B. underside C. drawback D. consequence

单选题______everybody's disappointment, the football match was put off.

单选题When President Kennedy spoke in Berlin from behalf of the American people, he was received with a show of enormous enthusiasm.

单选题The dichotomy postulated by many between morality and interests, between idealism and realism, is one of the standard clichés of the ongoing debate over international affairs.