用所给单词的适当形式填空。（共6小题；每小题1分，满分6分）
小题1: December is the __________ (twelve) month of a year.
小题2: As we all know, the silk dress feels __________ (soft).
小题3: She said to the twins, “Help ___________ (you) to some fruit.”
小题4: You should do your homework as ___________ (careful) as your sister.
小题5: The foreign teacher gave us some ___________ (advice) on how to learn English.
小题6: __________ (teach) high school students in a poor mountain village may not sound like fun to you.