根据短文内容, 选择正确答案。   

A

A good reader is like a driver. He must change his reading speed (速度) to fit what he is reading and what he is reading for, just as a driver does to fit the road condition (状况). A good reader may be able to read a thousand words per minute (WPM)(词/每分钟) but he won't use that speed for everything he reads. A good reader doing research (研究) may read at the speed of 1, 000 WPM when he looks for something for a report in the library. Butoncehe finds what he needs, he may slow down to 100 WPM.A good reader may read newspapers and storybooks at the speed of 600 WPM. But he may read his science or math books at the speed of 150 WPM. Just as a driver has a wide change of driving speed, a good reader has a wide change of reading speed.