根据句意，用括号内所给单词的适当形式填空。

1. I like P.E. best. Because my P.E. teacher is very _____ (friend) to us.

2. — Where is your bedroom?

    — It's on the _____ (two) floor.

3. — Thank you for your help. 

    — It's my _____ (please).

4. All the books are on these _____ (shelf). You may go to find the book you want to borrow.

5. Kangkang likes _____(dance) at the party, because it's interesting.