英语：Unit 1《Getting along with others》
教案-Grammar（译林牛津版必修5）
Ⅰ. 不定式句法功能
1. 作主语：The cat said, “To take roller coaster” is terrible.
不定式短语作主语时，可以直接放在句首，但在很多情况下，尤其是在疑问句和感叹句中，往往放在谓语之后，而用先行代词it作形式主语。
→ The cat said, “It’s terrible to take roller coaster.”
How long did it take you to take roller coaster?
How terrible it is to take roller coaster?
不定式作主语常见句型：
a) It is + adj. (easy, important, difficult…) + 不定式
b) It is + n. (a pity, a pleasure, one’s duty, a shame) + 不定式
eg. It’s my duty to teach you how to be a student of No.3 Middle School.
c) It takes/needs/requires + some time (hours, months, days, patience…) + 不定式
eg. It requires patience to be a good teacher.
