【单选题】

What do we think with Only the brain Hardly. The brain is tike a telephone exchange. It is the switchboard, but not the whole system. Its function is to receive incoming signals, make proper connections, and send the messages through to their destination. For efficient service, the body must function as a whole.

But where is the "mind’ Is it in the brain Or perhaps in the nervous systemAfter all, can we say that the mind is in any particular place It is not a thing like a leg or even the brain. It is a function, an activity.Aristotle, twenty-three hundred years ago, observed that the mind was to the body what cutting was to the ax. When the ax is not in use, there is no cutting. So with the minD、"mind" saidCharles H • Woolbert, "is what the body is doing."
If this activity is necessary for thinking, it is also necessary for carrying thought from one person to another. Observe how people go about the business of ordinary conversation. If you have never done this painstakingly (费力的), you have a surprise in motion. Their heads are continually nodding and shaking sometimes so vigorously that you wonder how their necks can stand the strain.
Even the legs and feet are active.As for the hands and arms, they are seldom still for more than a few seconds at a time.
These people, remember, are not making speeches. They are merely common folk trying to make others understand what they have in minD、They are not conscious of movement. Their speech is not studieD、They are just human creatures in a human environment, trying to adapt themselves to a social situation. Yet they converse, not only with oral language but with visible actions that involve practically every muscle in the body.
In short, because people really think all over, a speaker must talk all over if he succeeds in making people think.
It can be inferred from the passage that the basic function of bodily activity in speech is to ______.
A、make the listener feel emotional
B、make the speaker understood
C、amplify or intensify the speaker’s spoken words
D、convey the speaker’s implied meaning to the listener