[语法初识]

原句感知 自主探究 ①It was foolish of you to lie to your teacher.

②It's no use trying to persuade him to change his mind.

③Our duty is to help the young children to grow better.

④Our work is serving the people.

⑤People want to know who Mona Lisa is and why she is smiling.

⑥The building being built is a new shopping mall.

⑦The bird was lucky and escaped being caught.

⑧Painted by Leonardo da Vinci in the year 1503－1506, the Mona Lisa is a mysterious masterpiece. (1)句①②中黑体部分在句中均作主语。句③④中黑体部分在句中均作表语。句⑤中黑体部分在句中作宾语。

(2)根据句①②可知，动词不定式和动词­ing形式作主语时，可以用it作形式主语。

(3)句⑥⑦可知，黑体部分为动词­ing形式的被动式，在句中分别作定语和宾语。

(4)句⑧中黑体部分为过去分词在句中作状语。 　　

　　[语法剖析]

语法点一 非谓语动词的基本形式

时态形式 主动式 被动式