听力原文：M: I went out with my girlfriend to a nice restaurant last night and I noticed that many people shouted for the bill. It was quite annoying and dislikable. W: (19) That seems to be very common among people now but I have to say, it is a little impolite in such a public Place. M: I can't agree more. I just thought I'd ask you and see what you thought of it. Anyway, what did you do yesterday evening? W: Well, I planned to go to the gym, but it was really a warm evening, (20) so I walked in the park for a couple of miles. Actually, several other people had the same idea. I saw Bill. M: Did you? How is he these days? W: He is OK. We just stopped and chatted for a few minutes. Then he got a call and went back. M: I see. So can you suggest a few exercises to help me stretch my muscles a little? W: Sure. One good way is to do push-ups. M: When I do push-ups, should I bend my elbows so that my nose touches the ground? W: Actually, you don't need to bend your elbows that much. Bend them so that your arms are at a 90 degree angle. (21)The most important thing is to remember to keep your body straight. Many people bend their bodies at the waist, which reduces the effectiveness of the exercise. M: What's a good exercise for my chest muscles? W: Lie on your back, hold a weight in each hand and stretch your arms out side of your body. Then lift the weights up, keeping your arms straight all the time. (20)