4．Science can't explain the power of pets，but many studies have shown that the company of pets can help lower blood pressure （血压） and raise chances of getting well from a heart attack，reduce loneliness and spread all-round good cheer．
Any owner will tell you how much joy a pet brings．For some，an animal provides more comfort than a husband or wife．A 2002study by Karen Allen of the State University of New York measured stress （紧张） levels and blood pressure in people---half of them pet owners---while they performed 5minutes of mental arithmetic （算术） or held a hand in ice water．Subjects completed the tasks alone，with a husband or wife，a close friend or with a pet．People with pets did it best．Those tested with their animal friends had smaller change in blood pressure and returned most quickly to baseline heart rates．With pets in the room，people also made fewer math mistakes than when doing in front of others．It seems people feel more relaxed （放松） around pets，says Allen，who thinks it may be because pets don't judge．
A study reported last fall suggests that having a pet dog not only raises your spirits but may also have an effect on your eating habits．Researchers at Northwestern Memorial Hospital spent a year studying 36fat people and their equally fat dogs on diet-and-exercise programs； a separate group of 56people without pets were put on a diet program．On average，people lost about 11pounds，or 5% of their body weight．Their dogs did even better，losing an average of 12pounds，more than 15% of their body weight．Dog owners didn't lose any more weight than those without dogs but，say researchers，got more exercise overall---mostly with their dogs---and found itworth doing．
67．What does the text mainly discuss？A
A．What pets bring to their owners．
B．How pets help people calm down．
C．People's opinions of keeping pets．
D．Pet's value in medical research．
68．According to Allen，why did the people do better with pets around when facing stressful tasks？C
A．They have lower blood pressure．
B．They become more patient．
C．They are less nervous．
D．They are in higher spirits．
69．What does the underlined word"it"mean？B
A．Having a pet
B．Getting more exercise
C．Losing weight
D．Being on a diet program
70．The research mentioned in the last paragraph reports thatD．
A．dogs lost the same weight as people did
B．people without dogs found the program unhelpful
C．dogs liked exercise much more than people did
D．people with dogs did more．
分析 本文属于说明文阅读，作者主要向我们介绍了科学不能解释宠物对我们的影响，比如有宠物的陪伴可以帮助降低血压，提高心脏病恢复的机会，并且可以感到放松，拥有一只宠物狗也会改变你的饮食习惯，使你得到更多的锻炼．
解答 67．答案：A．主旨大意题．通读全文可知，本文主要讲述了宠物给它们的主人带来的好处．故选A．
68．答案：C．细节理解题．根据"It seems people feel more relaxed （放松） around pets，says Allen，who thinks it may be because pets don't judge．"可知，人们和宠物在一起更放松，不紧张．故选C．
69．答案：B．推理判断题．根据"Dog owners didn't lose any more weight than those without dogs but，say researchers，got more exercise overall---mostly with their dogs---and found it worth doing．"可知，有狗的人经常锻炼．并且可推测出it指的是"getting more exercise"．故选B．
70．答案：D．主旨大意题．根据"Dog owners didn't lose any more weight than those without dogs but，say researchers，got more exercise overall"可知，养狗的人锻炼得更多．故选D．
点评 本文是一篇说明文，题目涉及主旨大意题，细节理解题，推理判断题，做题时应结合文章上下文内容并根据所给选项的含义进行分析，从而得出正确答案．切记胡乱猜测，一定要做到有理有据．
