Passage Two Eye contact is a nonverbal (非语言的) technique that helps the speakers 'sell' thier ideas to an audience. Besides its persuasive powers, eye contact helps hold listeners' interest. A successful speaker must maintain eye contact with an audience. To have good relation with listeners, a speaker should maintain direct eye contact for at least 75 percent of the time. Some speakers focus only on their notes. Others look over the heads of their listeners. Both are likely to lose audience's interest and respect. People who maintain eye contact while speaking, whether from a podium or from across the table, are regarded not only as exceptionally friendly by their target but also as more believable and earnest. To show the power of eye contact in daily life, we have only to consider how passers-by behave when their glances happen to meet on the street. At one extreme are those people who feel obliged to smile when they make eye contact. At the other extreme are those who feel uncomfortable and immediately look away. To make eye contact, it seems, is to make a certain link with someone. Eye contact with an audience also lets a speaker know and monitor (观察) his listeners. It is, in fact, essential to analyze an audience during a speech. Visual feedback (视觉反馈) from the audience can indicate that a speech is boring, that the speaker is talking too much about a particular point, or that a particular point requires further explanation. As we have pointed out, visual feedback from listeners should play an important role in shaping a speech as it is delivered. What does the writer believe about a speaker's eye contact?