Section Ⅲ　Grammar--动词­ing形式(Ⅰ)

　　[语 境 自 主 领 悟]

先观察原句 后自主感悟 1.Will, still watching, saw the cat behave curiously.

2.When it had gone past he crossed the road, keeping his eyes on the spot where the cat had been investigating.

3.While sitting by a pool, Ferdinand sees a frog.

4.Before leaving his kingdom, he calls his son to him.

5.Not knowing her address, I can't write to her to express my gratitude.

6.Having lived with the girl for 5 years, we all know her very well. 1.六个例句中动词­ing形式的逻辑主语都是句子的主语。

2.由句5可知，动词­ing形式的否定式是在其前加not。

3.在句3中，动词­ing形式短语前用while，为了强调与谓语动词的动作同时发生；在句4中，动词­ing形式短语前用before，为了强调在谓语动词的动作之前发生。

4.由句6可知，动词­ing 形式的完成式为having done。 　　[语 法 精 要 点 拨]

　　考点一　动词­ing形式作状语的基本用法

　　动词­ing形式作状语时可以表示时间、原因、条件、让步、结果、方式或伴随动作，作方式状语和伴随状语时可以变为并列分句，作其他状语时也可以变为相应的状语从句。它的位置比较灵活，可以置于句首、句中或句末，有时用逗号分开，有时不用。一般来说，作时间、原因、条件或让步状语时，通常位于句子的前部；作结果、方式或伴随状语时，通常位于句子的后部。

状语类型 例句 时间 Hearing the good news, they went wild with joy.

(＝When they heard the good news, they went wild with joy.)

听到这个好消息，他们高兴得发了狂。 原因 Getting up late, he missed his early train.

(＝Because he got up late, he missed his early train.)

由于起床晚了，他没有赶上早班火车。 条件 Turning to the left, you will find the school.

(＝If you turn to the left, you will find the school.)

向左拐，你就会发现那所学校。