一、单项选择（30分）
从每小题的选项A、B、C、D中选出一个能填入句中空白处的最佳答案。
1. The river is very_____ . It’s too dangerous to swim in it alone.
A. deep B. correct
C. energetic D. silly
2. He doesn’t do his homework_____. So he always makes some mistakes.
A. careful enough B. enough careful
C. carefully enough D. enough carefully
3. It’s silly_____ you_____your car at such a low price.
A. for; to sell B. of; to sell
C. for; sell D. of; sell
