Passage Three
　　Questions 31 to 35 are based on the following passage.
　　Crying is hardly an activity encouraged by society. Tears, be they of sorrow, anger, on joy, typically make Americans feel uncomforuble and embarrassed. The shedder of tears is likely to apologize, even when a devastating (毁灭性的) tragedy was the provocation. The observer of tears is likely to do everything possible to put an end to the emotional outpouring. But judging form 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 responset, 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 clicit assistance form 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 cmotion. 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 Teat Analysis Laboratory Dr.Peter Kastl and his colleagues report that they can use tears to detect drug abuse and exposure to medication(药物), 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.

　　31. It is known from the first paragraph that ________.
　　A) shedding tears gives unpleasant feelings to American
　　B) crying may often imitate people or even result in tragedy
　　C) crying usually wins sympathy from other people
　　D) one who sheds tears in public will be blamed

　　32. What does “both those responses to tears”(Line 6, Para, 1) refer to?
　　A) Crying out of sorrow and shedding tears for happiness.
　　B) The embarrassment and unpleasant sensation of the observers.
　　C) The tear shedder’s apology and the observer’s effort to stop the crying.
　　D) Linking illness with crying and finding the chemical composition of tears.

　　33. “Counterproductive” (Lines 6-7, Para,1) very probably means “________”.
　　A) having no effect at all
　　B) leading to tension
　　C) producing disastrous impact
　　D) harmful to health

　　34. What does the author say about crying?
　　A) It is a pointless physiological response to the environment.
　　B) It must have a role to play in man’s survival.
　　C) It is meant to get attention and assistance.
　　D) It usually produces the desired effect.

　　35. What can be inferred from the new studies of tears?
　　A) Emotional tears have the function of reducing stress.
　　B) Exposure to excessive medication may increase emotional tears.
　　C) Emotional tears can give rise to “dry eye” syndrome in some cases.
　　D) Environmental pollutants can induce the shedding of emotional tears.