翻译下列短语并完成句子。

1. a balanced diet ____

2. keep the balance of nature ____

3. keep one' s balance___

4. lose one's balance ( =be out of balance)___

5.  He ______ and hurt himself when he went upstairs.

6. It is difficult to for you to _____ onan icy pavement.

毛 * * 思想成熟是在（）。

A.党成立初期和国民革命时期

B.土地革命战争前中期

C.土地革命战争后期和抗战时期

D.建国以后