一. 教学内容：
9A Unit 3 Grammar
二. 教学目标：
1. To-infinitives 动词不定式
2. “wh” words + to-infinitive 疑问词+不定式动词
3. Sentence types 句子的四种类型
【具体教学过程】
（一）To-infinitives 动词不定式
Subject (主语)
To plant trees every year is necessary.
不定式作主语常能换成形式主语 “it”.
To eat too much is unhealthy for you.
