A、Because they have to stand still. B、Because they are too nervous to look at the audience. C、Because they often look at somethi

Moderator:
    Good evening, ladies and gentlemen. It’s my great honor to introduce our speaker for today’s lecture, Dr. Charles Black. Charles Black, a professor of linguistics at University of Berkeley, has written many articles and books on public speaking. Tonight, we’ll focus on the physical message of presentation, which is a very essential part in public speaking. Welcome, Dr. Black.   
    Dr. Black:
    Thank you! Today, we return to the subject of successful public speaking centering on the physical message of presentation. Some call this "body language" which includes posture, eye contact and gestures—how you move your hands or arms.
    When people are making a presentation, they’re really nervous. But in addition to that, they’re really nervous because of their English, and their lack of confidence, lack of experience in their English. They’re trying to figure out the grammar, and they’re having all kinds of difficulty doing that, and also controlling their bodies.
    New public speakers know that they should look at the audience while they are speaking. But they look at their notes on a piece of paper or at the screen if they have an electronic presentation. With posture, the typical problem is that they are often moving back and forth, and they’re not facing the audience. They’ll often be facing the whiteboard or the screen with slides and be talking to that rather than talking to the audience.
    Same thing with eye contact. They find it really, really difficult making eye contact with the audience, because they’ll be looking at their notes, or at their computer, or at the screen, or even at the floor. The problem of having notes and trying to talk from notes often is a big problem. So they have trouble with eye contact.
    The best way to avoid this problem is to use images and a few words for notes instead of sentences. The image should help communicate the point you want to make. Writing a few words with the image on your slide helps you remember that point. Then you can look at the audience while speaking.
    So, next time when you make a public presentation, remember to use your body language.
    Questions 16 to 19 are based on the recording you have just heard.
    16.What does the moderator say about the physical message of presentation?
    17.Which of the following does body language NOT include?
    18.Why do new public speakers fail to make eye contact with the audience?
    19.According to Dr. Black, what can help you remember the point of your presentation?