根据汉语用所学短语的正确形式填空。

1. Galileo's observations show that Copernicus, another great astronomer, was right and that the earth 

    moves around the sun, not ______ (相反).

2. Three years ______ (过去), but he was still alone.

3. The old should be ______ (尊敬).

4. Our teachers ______ (不遗余力) to help us in our daily life.

5. He ______ (充当) chairman in my absence last year.