阅读下面材料，在空白处填入适当的内容(不多于3个单词)或括号内单词的正确形式。
Jonny:  Hey! I'm just practicing Tai Chi(太极).Would you like to join me?
Peter:  I know nothing about it. Is it difficult?
Jonny:  It seems easy, but you need a lot of practice. You just follow me like this.
Peter:  OK. Don't laughme. I may look funny.
Jonny:  Bend your knees slightly and reach out your arms like tree branches, naturally and(soft). Try to keep your body straight. Move slowly , then be sure to keep your balance and don't let your body shake.
Peter:  I cannot control my body well. My legs become(pain)
Jonny:  Keep(hold) your position for a while .It helps develop your strength and flexibility .Raise your leg and letstay in the air for seconds.
Peter:  I feel my legs shaking . I cannot do this any longer.
Jonny:  Be patient! Tai Chi(call)"shadow boxing" in English. It asks you to act like water: to be flexible as wellstrong. In real competition, a Tai Chi master borrows the strength of the competitor and uses this energy to fight back. The(hard) you try to beat him, the more likely you will get hit. He controls you!
Peter:  Unbelievable! Oh...,you don't mind, I'll stop and take a deep.