按风化作用的性质，一般将其分为（）、（）和（）。
参考答案：物理风化作用、化学风化作用、生物风化作用
用括号内所给单词的适当形式填空。
1. We should often exercise to stay _____ (health).
2. Sam says, "Mary is _____ (heavy) than me".
3. I can't go to school, I have to rest today, because I have a _____ (head).
4. We go to the movies _____ (one) a month.
5. Chinese medicine is now popular in many _____ (west) countries.
犀牛角
