4. According to the passage, a conversation between two Americans may break down due to .
A. one temporarily glancing away from the other
B. eye contact of more than one second
C. improperly-timed ceasing of eye contact
D. constant adjustment of eye contact
5. To keep a conversation flowing smoothly, it is better for the participants .
A. not to wear dark spectacles
C. not to glance away from each other
B. not to make any interruptions
D. not to make unpredictable pauses
参考答案：A C D C A
