A、To exchange ideas. B、To prove their value. C、To achieve success in life. D、To overcome their fear of silence. D选项均以To+ do开头表明，

Silence is unnatural to man. He begins life with a cry and ends it in stillness. In between he does all he eau to make a noise in the world, and he fears silence mow than anything else, Even his conversation is an attempt to prevent a fearful silence. If he is introduced to another person, and is number of pauses occur in the conversation, he regards himself as a failure. He knows that ninety-nine percent of human conversation means no more than the buzzing of a fly, but he is anxious to join in the buzz and to grove that he is a man and not a waxwork figure.
     The aim of conversation is, for the most part, to communicate ideas: it is to keep up the buzzing sound. There are, it must be admitted, different qualities of buzz; there is even a buzz that is as annoying as the continuous noise made by a mosquito. But at a dinner party one would rather be a mosquito than a quiet person. Most buzzing, fortunately, is pleasant to the ear, and some of it is pleasant even to the mind. He would be a foolish man if he waited until he had a wise thought to take part in the buzzing with his neighbors.
     Those who hate to pick up the weather as a conversational opening seem to me not to know the reason why human beings wish to talk. Very few human beings join in a conversation in the hope of learning anything new. Some of them are content if they are merely allowed to go on making a noise into other people’s ears. They have nothing to tell them except that they have seen two or three new plays or that they had food in a Swiss hotel. At the end of an evening, during which they have said nothing meaningful for a long lime. They just prove themselves to be successful conversationalists.