单选题Their business flourished when they moved to downtown are

单选题For the sake of your health, you should give up smoking______.

单选题Their experiment __________, Tom and Mary set out to write the report on the results.

单选题They found the lecture hard ______.

单选题Crying is hardly an activity encouraged by society. Tears, whether they are of sorrow, anger, or joy, typically make Americans feel uncomfortable and embarrassed. The shedder of tears is likely to apologize, even when a devastating tragedy was the provocation. The observer of tears is likely to do everything possible to put an end to the emotional outpouring. But judging from recent studies of crying behavior, links between illness and crying and the chemical composition of tears, both those responses to tears are often inappropriate and may even be counterproductive . Humans are the only animals definitely known to shed emotiomal tears. Since evolution has given rise to few, if any, purposeless physiological responses, it is logical to assume that crying has one or more functions that enhance survival. Although some observers have suggested that crying is a way to elicit assistance from others (as a crying baby might from its mother), the shedding of tears is hardly necessary to get help. Vocal cries would have been quite enough, more likely than tears to gain attention. So, it appears, there must be something special about tears themselves. Indeed, the new studies suggest that emotional tears may play a direct role in alleviating stress. University of Minnesota researchers who are studying the chemical composition of tears have recently isolated two important chemicals from emotional tears. Both chemicals are found only in tears that are shed in response to emotion. Tears shed because of exposure to cut onion would contain no such substance. Researchers at several other institutions are investigating the usefulness of tears as a means of diagnosing human ills and monitoring drugs. At Tulane University"s Tear Analysis Laboratory Dr. Peter Kastl and his colleagues report that they can use tears to detect drug abuse and exposure to medication, to determine whether a contact lens fits properly of why it may be uncomfortable, to study the causes of "dry eye" syndrome and the effects of eye surgery, and perhaps even to measure exposure to environmental pollutants. At Columbia University Dt. Liasy Faris and colleagues are studying tears for clues to the diagnosis of diseases away from the eyes. Tears can be obtained painlessly without invading the body and only tiny amounts are needed to perform highly refined analyses.

单选题A good night's sleep is a ______of having good recall in the weeks ahead, scientists have found.

单选题We all love a hero, and rescue dogs are some of the biggest heroes of all. You will often find them going above and beyond duty to save someone, risking--and at times losing--their lives in the proces

单选题—Have you moved into the new house?—Not yet. The room ______ .

单选题He is ______ of an actor.

单选题The figure of illiteracy in Europe makes up ______.

单选题It is the central government that has ______ the coastal economies preferential policies.

单选题 Evidence came up ______ animals will behave abnormally if there is going to be an earthquake.

单选题The application of 3G is on the upswing in China; however, the era of 4G has also begun.

单选题If you refuse to pay,I shall ______ against you． A．take actions B．take action C．taking action D．to take actions

单选题He is too young to be able to ______ between right and wrong.

单选题______ the end, he finished doing his homework and went to sleep. [A] At [B] In [C] On

单选题Peter was seen crying when he came out of the office. We can deduce that he must have been punished.

单选题The idea for the new project came to Jack ______ to his study recently.

单选题An action that is lavishly rewarded as soon as it is performed is well on its way to becoming a habit.