甲与乙订立合同,规定甲应于2003年8月1日交货,乙应于同年8月7日付款。7月底,甲发现乙财产状况恶化,遂提出中止履行合同,乙不同意。基于上述因素,甲于8月1日未按约定交货。依据《合同法》的有关规定,下列表述正确的是 ()
A. 甲有权不按合同约定交货,除非乙提供了相应的担保
B. 甲无权不按合同约定交货,但可以要求乙提供相应的担保
C. 甲无权不按合同约定交货,但可以仅先交付部分货物
D. 甲应当按合同约定交货,不得随意中止合同履行
Part A
Directions: Read the following four texts. Answer the questions below each text by choosing A, B, C or D. (40 points)
You might be forgiven for thinking that sleep researchers are a dozy bunch. Most of the other things people do regularly—eat, excrete, copulate and so on—are biologically fairly straightforward: there is little mystery about how or why they are done. Sleep, on the other hand, which takes up more of most people's time than all of the above, and which attracts plenty of study, is still fundamentally a mystery.
The one view shared by all is that sleep matters. For evidence, look no further than the experiments led by Allan Rechtaschaffen and Bernard Bergmann at the University of Chicago in the 1980s. They kept experimental rats awake around the clock in an environment where control rats were allowed as much sleep as they wanted. The sleep-deprived rats all died within a month.
Carol Everson worked with the Chicago team as a graduate student and now has a job at the National Institutes of Health in Bethesda, Maryland. While repeating the Chicago experiments she was struck by the fact that, although the sleep-deprived rats showed no obvious symptoms of particular diseases—and no such signs were picked up in post-mortems—their emaciation and generally sorry state was reminiscent of that which befalls many terminal cancer patients and AIDS patients, whose immune systems have packed up. While Dr. Everson does not claim to have hard and fast proof that sleep is needed for resistance to infection, her work does point that way—as does the re search of others around the world.
Another approach is to look for chemicals that cause sleep; from these, you should be able to start telling a biological story which will eventually reveal the function of sleep. Peter Shiromani of Harvard Medical School has found a protein that builds up at high levels in chronically sleep-deprived cats, but disappears within an hour if the animals are allowed 45 minutes of recovery sleep. Researchers at the University of Veron have found something similar. But no one chemical tells the whole story.
So new ways of inducing sleep may soon be available; an understanding of its purpose, though, remains elusive. In this, sleep is like the other great biological commonplace that is still mysterious: consciousness, which is also easily altered chemically but not too well under stood. No one knows how Consciousness arises, or what, if anything, it is for(though there are a lot of theories). Almost the only thing that can be said about it for certain is that you lose it when you fall asleep. Solving the mystery of sleeping and waking might require new insights into the consciousness that is lost and regained in the process. Putting it this way makes the problem sound rather grander, and the lack of progress so far look a bit less dozy.
Why does the writer say "You might be forgiven for thinking that..."?
A. Solving the mystery of sleeping and waking requires new insights.
B. Most of the other things people do regularly are biologically straightforward.
C. The problem sounds rather grand.
D. We still lack for progress though we've spent much more time studying it.