用所给单词的适当形式填空。

1. December is the ________ (twelve) month of a year.

2. As we all know, the silk dress feels ________ (soft).

3. She said to the twins, "Help ________ (you) to some fruit."

4. You should do your homework as ________ (careful) as your sister.

5. The foreign teacher gave us some ________ (advice) on how to learn English.

6. _______ (teach) high school students in a poor mountain village may not sound like fun to you.