A、It is a sign of one’s friendliness. B、It is a sign of one’s unfriendliness. C、It makes people feel happy. D、It makes people fe

Nonverbal communication has to do with gestures, movements and closeness of two people when they are talking. The scientists say that those gestures, movements and so on have meaning which words do not carry.
   For example, the body distance between two speakers can be important. North Americans often complain that South Americans are unfriendly because they tend to stand close to the North American when speaking, while the South American often considers the North American to be "cold" or "distant" because he keeps a greater distance between himself and the person he is speaking to. The " eye contact" provides another example of what we are calling nonverbal communication. Scientists have observed that there is more eye contact between people who like each other than there is between people who don’t like each other. The length of time that the person whom you are speaking to looks at your eyes indicates the amount of interest he has in the things you are talking about.
   On the other hand, too long a gaze can make people uncomfortable. The eyes apparently play a great part in nonverbal communication. Genuine warmth or interest, shyness or confidence can often be seen in the eyes. We do not always consider a smile to be a sign of friendliness. Someone who is always smiling with little apparent reasons often makes us uneasy.
Questions 19 to 21 are based on the passage you have just heard.
19. Which of the following about nonverbal communication is true?
20. Which of the following is not true?
21. How do people think about constant smiling without apparent reason?