用所给词的适当形式填空。

1. The ____ (leaf) on the trees are turning green.

2. Our teacher is very____ (friend). We all like her very much.

3. My father usually ____ (relax) one hour at noon every day.

4. Tom, please do your homework ____ (one).

5. Let's____ (go) to see the panda first.

接触线的功用是保证质量良好地向（）供电。