根据句意和汉语提示,在空白处填入适当的单词.

1. May I ___________(借) your dictionary? I left mine at home.

2. Everyone should take an active part in _______________(保护)the environment.

3.The confident young man will have his ______________(二十) birthday.

4. Everyone should try to be _____________(有礼貌的) and helpful to others.

5. China has got a _______________( 人口) of 1.3 billion.