单项选择题

Once you’re prepared for a situation, you’re 50 percent of the way toward overcoming nervousness. The other 50 percent is the physical and mental control of nervousness; adjusting your attitude so you have confidence, and control of yourself and your audience.
I was in the theater for many years and always went to work with terrible stage fright—until I was in The King and I. While waiting offstage one night, I saw Yul Brynner, the show’s star, pushing in a lunging (冲) position against a wall. It looked as though he wanted to knock it down. "This helps me control my nervousness," he explained.
I tried it and, sure enough, freed myself from stage fright. Not only that, but pushing the wall seemed to give me a whole new kind of physical energy. Later I discovered that when you push against a wall you contract the muscles that lie just below where your ribs (肋骨) begin to splay (展开). I call this area the "vital triangle".
To understand how these muscles work, try this: sit in a straight-backed chair and lean slightly forward. Put your palms together in front of you, your elbows pointing out the sides, your fingertips pointing upward, and push so that you feel pressure in the heels of your palms and under your arms.
Say ssssssss, like a hiss (嘶嘶声). As you’re exhaling (轻轻发出) the s, contract those muscles in the vital triangle as though you were rowing a boat, pulling the oars (船桨) back and up. The vital triangle should tighten. Relax the muscles at the end of your exhalation, then inhale gently.
You can also adjust your attitude to prevent nervousness. What you say to yourself sends a message to your audience. If you tell yourself you’re afraid, that’s the message your listener receives. So select the attitude you want to communicate. Attitude adjusting is your mental suit of armor (铠甲) against nervousness. If you entertain only positive thoughts, you will be giving out these words: joy and ease, enthusiasm, sincerity and concern, and authority.
Yul Brynner pushed the wall in order to ______.