What may happen if we cannot hear ourselves thinkA

单项选择题

The sense of sound is one of our most important means of knowing what is going on around us. Sound has a waste product, too, in the form of noise. Noise has been called unwanted sound. Noise is growing and it may get much worse before it gets any better.
Scientists, for several years, have been studying how noise affects people and animals. They are surprised by what they have learned. Peace and quiet are becoming harder to find. Noise pollution is a threat that should be looked at carefully. There is a saying that it is so noisy that you can’t hear yourself think. Doctors who study noise believe that we must sometimes hear ourselves think. If we don’t, we may have headaches, other aches and pains, or even worse mental problems. Noise adds more tension (紧张) to a society that already faces enough stress. But noise is not a new problem. In ancient Rome, people complained so much about noise that government stopped chariots (四轮马车) from moving through the streets at night!
Ways of making less noise are now being tested. There are even laws controlling noise. We cannot return to the "good old days" of peace and quiet. But we can reduce noise—if we shout loudly enough about it.

What may happen if we cannot hear ourselves think

A. We may forget what we have thought about.
B. Our thoughts may be disturbed.
C. Our mind may be harmed.
D. We may have difficulty finding the right words.