听力原文： Has this ever happened to you? You're sitting in the office one morning. You're trying to work, but the working is boring and your mind is not on what you are doing. Suddenly, you think of an old friend. You haven't seen her or heard from her for a long time. You wonder how she is and what she's been doing. When you get home from work, the phone is ringing, before you answer it, you think you know who the caller is. And you are right! It's your old friend! She says, 'I was thinking about you this morning. I called to find out how you are and what you've been doing.' Why were you and your friend thinking about one another at the same time? How did you know who was calling? After you and your friend recovered from the surprise, did one of you mention ESP? Everyone talks about ESP, or extrasensory perception, but no one really understands what it is. Scientists who have studied it say that it is knowing something without using any of the five senses—seeing, hearing, smelling, tasting, and touching. But why can't we explain how it works or why some people have it and others don't? There are 3 kinds of ESP. Telepathy is knowing what another person is thinking or feeling (i.e. when you and your friends had the same thoughts at the same time). Clairvoyance is 'seeing' what is happening in a place that is far away. Precognition is knowing what is going to happen before it happens(i.e. when you knew who was calling). Do you have ESP? There are tests you can use to find out. To test yourself and your friends for telepathy, make cards out of 5 small pieces of heavy paper. Put a different mark on each card—a star, a circle, a cross, square, and some wavy lines. Ask your friends to hold up one card at a time and look at the symbol. Then try to 'read' your friends' mind to find out what the symbol on each card is. Ask your friends to write down your answers and to record what the symbol really was. Do this 5 times. If you have more than five correct answers out of 25, your ESP is working! Here is a clairvoyance experiment. Gather 5 different objects—perhaps a key, a pencil, a watch, a book and a cup—and put them on a tray. Ask everyone in the room to look at the things for a few minutes. Then choose one person and ask him or her to take the tray to the next room, put one of the objects in the center of that room, and put the tray and the other things aside. When the person returns, ask everyone to concentrate on the object in the center of the room. When each of you thinks you know what the object is, write It on a piece of paper. Do this experiment several times. To test for precognition, you can use the same 5 objects. Place them in a circle. Ask each person to write down the name of the object thatwill be placed in the center of the next room. Then ask one person to take all of the objects to that room and place one thing in the center. When the person returns, look at each piece of paper. Did you or any of your friends predict the future? Many books have been written about the fascinating and frustration study of ESP. But no one has been able to explain it. ES?remains a mystery. Questions: 16.What does ESP refer to in this article? 17.Which of the following is true? 18.Which of the following can test the existence of ESP? 19.What can a person do if she or he has telepathy? 20.According to the article, which of the following testees has ESP? (36)