用所给单词的正确形式填空。  

1. He is a little                (heavy) this year than last year.

2. Hong Kong is _             (warm) than Beijing in winter.  

3. —Is this city _              (hot) than that one？    

    —No , it's                  (cold) .

4. Miss Liu is                   (busy) than any other teacher in our school.

5. Tony's dictionary is _             (new) than his sister's.