夏季雨后，蚯蚓常会爬到地面上活动，原因是 ( )
A．土壤中缺乏氧气
B．土壤中缺乏食物
C．土壤中太阴暗
D．寻找配偶繁殖后代
答案：A
题目分析：蚯蚓靠湿润的体壁进行呼吸，空气中的氧气先溶解在体壁的粘液里，然后渗透到体壁内的毛细血管中的血液里，血液中的二氧化碳也通过体壁排出体外。因此，蚯蚓长期生活在湿润的环境中，夏季雨后，蚯蚓常会爬到地面上活动，原因是因为大雨过后过多的雨水会将土壤中的空气排挤出去了同，这样土壤中缺乏氧气，于是蚯蚓就爬到地面上活动，故选项A符合题意。
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| Some people say they have an answer to the problems of car crowding and pollution. In many cities, hundreds of people __1__ bikes to work every day. In New York City, some bike riders have even founded a group: Bike for a Better City. They say if __2__ people rode bikes to work, there would be fewer cars and less dirty air. For several years this group had tried to get help for bike riders. They want to have special roads for bikes only, because __3__ bike and cars use the same roads, there may be accidents. Bike for a Better City feel if there were bike roads, more people would use bikes. But __4__ bike roads have been ready yet. Not everyone thinks it is a good__5__. Drivers don't like it, and some shop owners don't __6__ . And most people live __7__ far from the city to travel by bike. Still, __8__ has been done about it. On Saturdays and Sundays, the largest open park in New York is __9__ to cars, and the roads may be used by bikes only, but the group still says this is not enough and goes on fighting __10__ bike roads. | |||
| ( ) 1. A. on ( ) 2. A. fewer ( ) 3. A. until ( ) 4. A. no ( ) 5. A. hope ( ) 6. A. so ( ) 7. A. very ( ) 8. A. everything ( ) 9. A. closed ( ) 10. A. get | B. ride B. less B. for B. only B. way B. and B. quite B. something B. open B. to get | C. by C. many C. when C. some C. help C. neither C. too C. anything C. opening C. ask | D. take D. more D. why D. many D. idea D. either D. so D. nothing D. closing D. to ask |