4. It is well known that human tears often serve to moisten the eye, protect it from infection, and wash away irritants; such tears are called irritant or reflex tears. Dr. Field hypothesizes that emotional tears have a different biological function. She suggests that by shedding tears when under emotional stress people excrete harmful chemicals that build up in such body fluids as blood serum during emotional stress. Each of the following, if true, provides some support for Dr. Field’s hypothesis EXCEPT: (A) The people most likely to cry when undergoing emotional stress are less likely to suffer from stress-related diseases than is the population at large. (B) If a local anesthetic is applied to the surface of the eye, irritant and reflex tears are inhibited, but emotional tears are not. (C) The chemical composition of tears that are induced by grit in the eye is identical to the composition of tears induced by emotional stress. (D) The concentration of a substance that the body produces only under conditions of emotional stress is thirty times greater in tears than in blood serum. (E) Patients who suffer from a condition that prevents secretion of tears display a slower than normal physiological recovery from emotional stress. 答案c mineb 我知道c是对的,但b为什么不对那? 如何排除b?麻醉剂被用到眼睛上,眼睛就没有感觉了,所以irritant and reflex tears are inhibited那为什么but emotional tears are not?麻醉剂会给人造成精神压力吗?这是常识?
[此贴子已经被作者于2005-11-9 7:14:29编辑过] |