4．Science can't explain the power of pets，but many studies have shown that the company of pets can help lower blood pressure （血壓） 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 （緊張） levels and blood pressure in people---half of them pet owners---while they performed 5minutes of mental arithmetic （算術(shù)） 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 本文屬于說明文閱讀，作者主要向我們介紹了科學(xué)不能解釋寵物對我們的影響，比如有寵物的陪伴可以幫助降低血壓，提高心臟病恢復(fù)的機(jī)會，并且可以感到放松，擁有一只寵物狗也會改變你的飲食習(xí)慣，使你得到更多的鍛煉．
解答 67．答案：A．主旨大意題．通讀全文可知，本文主要講述了寵物給它們的主人帶來的好處．故選A．
68．答案：C．細(xì)節(jié)理解題．根據(jù)"It seems people feel more relaxed （放松） around pets，says Allen，who thinks it may be because pets don't judge．"可知，人們和寵物在一起更放松，不緊張．故選C．
69．答案：B．推理判斷題．根據(jù)"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，有狗的人經(jīng)常鍛煉．并且可推測出it指的是"getting more exercise"．故選B．
70．答案：D．主旨大意題．根據(jù)"Dog owners didn't lose any more weight than those without dogs but，say researchers，got more exercise overall"可知，養(yǎng)狗的人鍛煉得更多．故選D．
點(diǎn)評 本文是一篇說明文，題目涉及主旨大意題，細(xì)節(jié)理解題，推理判斷題，做題時(shí)應(yīng)結(jié)合文章上下文內(nèi)容并根據(jù)所給選項(xiàng)的含義進(jìn)行分析，從而得出正確答案．切記胡亂猜測，一定要做到有理有據(jù)．
