Period Four　Grammar-Revising the ­ing form

感知以下课文原句，补全方框下的小题

1．Having collected and evaluated the information，I help other scientists to predict where lava from the volcano will flow next and how fast.

2．Having experienced quite a few earthquakes in Hawaii already，I didn't take much notice.

3．Having studied volcanoes now for many years，I am still amazed at their beauty as well as their potential to cause great damage.

4．Having swallowed the fruit，the girl became pregnant and later gave birth to a handsome boy.

1．在所有这4个句子中，现在分词短语都使用了完成式，原因是分词短语所表示的动作先于句子的谓语动作发生。

2．在句1和句4中，分词短语作时间状语；在句2中，分词短语作原因状语；在句3中，分词短语作让步状语。

一、动词­ing形式的时态、语态及意义

动词 形式 意义 以do为例 一般式doing 主动式doing 与句子主语构成逻辑上的主谓关系，与谓语动作同时发生，或基本上同时发生 被动式being done 与句子主语构成逻辑上的动宾关系，且与谓语动作同时发生 完成式having done 主动式having done 与句子主语构成逻辑上的主谓关系，且先于谓语动作发生 被动式having been done 与句子主语构成逻辑上的动宾关系，且先于谓语动作发生

Edison left America，preferring to giving up his fortune.