用方框内所给单词的适当形式填空。每空格限填一词，每词限用一次。

1. Are there any                between these two pictures?

2. Mike does               in math than I. He is good at math.

3. You should brush your                  twice a day.

4. Can I borrow your pen, please?              is at home.

5. Harbin is in           China and it's cold in winter.