Supposing she doesn't come，what shall we do?

要是她不来我们该怎么办？(supposing为连词，意为"假若")

Seeing (that) he didn't help others，no one would like to help him.

鉴于他不帮助别人，没有人愿意帮助他。(seeing (that)为连词，意为"鉴于......，由于......")

③当分词暗含的逻辑主语为表示泛指意义的one或you时，也无需考虑主语的一致性问题。

In doing such work，patience is needed.

＝When one does such work，patience is needed.

做这种工作需要耐心。

即时跟踪1　用所给动词的正确形式填空

1.Being(be) so angry，he couldn't go to sleep.

2.Holding(hold) guns，the soldiers rushed out.

3.The children went out of the school，talking(talk) and laughing(laugh).

4.The fish can eat a man in a few minutes，leaving(leave) only the bones.

5.Walking(walk) along the valley，we came across a large cave.

6.Arriving(arrive) at the worksite，she found them busy laying bricks.

7.When leaving(leave) the airport，they waved again and again to us.

二、动词­ing形式的时态

动词­ing形式的完成式：having done，表示分词的动作发生在主句谓语动词的动作之前，并且只能作状语，表示时间或原因(一般式表示动词­ing形式的动作与谓语动词的动作同时发生)。

Having lived in London for years，I almost know every place quite well.

在伦敦住了多年，我几乎对那儿的每个地方都很熟悉。(having lived作状语，表示原因，live动作发生在know动作之前)

Having worked for three hours(＝After he (had) worked for three hours)，he took a rest.

工作了三个小时之后，他休息了一下。(having worked作状语，表示时间，work动作发生在take a rest动作之前)

He stood there，waiting for a bus.

他站在那里等公共汽车。(waiting为动词­ing形式的一般式作状语，与stand动作同时发生)

即时跟踪2　句型转换

1.After he had washed his face，he went to the park.