6．Does stress cause gray hair？Many people believe that tension and stress can cause your hair to lose its color．In fact，it is an old wives tale that being upset all the time can result in premature graying．Here is a closer look at this situation and why some believe that this old wives tale could be true．
As one ages，the hairs on the head also age．In fact，just about everything on the human body begins to show signs of wear and tear after a while．The joints wear become stiff and skin wears and becomes wrinkled．Hairs on the head grow and eventually die．They are replaced，but in the process something else happens．
When new hairs are replaced，the color or pigment（色素）is also added to them．However，as one ages，this pigment becomes less and less available．At first，hairs will have a limited amount of pigment and they will appear to be grayish in color．In time，they will lose all of their pigment and will be white．Many things are known to cause graying and genetics is a very powerful factor．If one of your parents turns gray at an early age，there is a good chance that you will too．Some people begin the graying process in high school，while others may be over the age of forty．
Constant worry and tension can have many harmful effects on the human body．It is a known fact that stressful times can cause one to suffer hair loss．It would make sense that if it can cause these problems，perhaps it also may contribute to graying．However，there is no sound evidence to support this．
On the other hand，many medical professionals believe that there may be a link：between graying and a constant state of anxiety or tension．Does stress cause gray hair？There is no scientific evidence to support the theory，but it is best to avoid stressful situations．
24．The underlined phrase in the first paragraph most probably meansA．
A．silly remarks
B．clever remarks
C．exciting remarks
D．disappointed remarks
25．The second paragraph mainly tells usC．
A．every part of body is replaced with age
B．hairs will grow weak but not die
C．every part of body ages with age
D．skin becomes wrinkled with age
26．From the passage we can infer thatD．
A．sound evidence has been found．
B．gray hair has nothing to do with tension．
C．stressful situations can be of benefit．
D．stress causing gray hair is still in question．
27．What might play the most important role in the graying process？B
A．Genetics and the amount of sleeping time．
B．The amount of pigment and genetics．
C．The amount of food people eat and living environment．
D．Genetics and the amount of water people drink．
分析 本文就一个问题（压力会导致头发变白吗）展开了论述．很多人相信压力会使头发变白．文章从年龄和基因两方面谈论了头发变白的原因．持续的压力和忧虑对身体是有害的，可导致脱发．但究竟压力和头发变白之间是否有联系，目前尚无科学的证据．
解答 24．A词义猜测题．根据第一段"Many people believe that tension and stress can cause your hair to lose its color．"可知许多人认为紧张和压力会导致头发褪色变白．文章接下来谈到"In fact，it is…"以及下文可知，这种论断是没有科学依据的．由此可知，"an old wives tale"是指不经之谈或不科学的陈腐思想．故选A．
25．C主旨大意题．根据第二段As one ages，the hairs on the head also age．In fact，just about everything on the human body begins to show signs of wear and tear after a while．可知人体的每一部分都会随着年龄的增长而衰老．C选项恰当地概括了该段的大意．故选C．
26．D推理判断题．根据倒数第二段However，there is no sound evidence to support this．以及最后一段"There is no scientific evidence to support the theory…"，可知压力是否会引起头发变白尚无定论．故选D．
27．B细节理解题．根据第三段"At first，hairs will have a limited amount of pigment and they will appear to be grayish in color．In time，they will lose all of their pigment and will be white．Many things are known to cause graying．and genetics is a very powerful factor．"可知色素和基因在头发变白的过程中起着重要的作用．故选B．
点评 本文考察学生的理解推断能力以及细心程度，只要抓住文章的关键词，采用寻读的方法查找细节，就能找到正确答案．
