题目

已知ab2c3d4e5<0。下列判断正确的是（） A . abcde<0 B . ab2cd4e<0 C . ab2cde<0 D . abcd4e<0 答案：B　　  Some people believe that they can study just as well or even better when the music - makers are turned on. Experiments among workers, however, have proved that they work better when there is no noise. They get their work done quicker and better when the place is quiet. Actually, the student who studies to the tunes of the hi-fi set has to waste part of his energy ignoring the tape deck or radio. If he does not fight the sounds, then, while he is listening, he is an inefficient studier. Noise, even good music, uses up some of the energy that is needed for concentration. The facts seem to show that it is not true that people can study better with music in the air. A suitable title for this passage is  ________. A．Radio music and study B．Experimentation C．Noise D．Music