简化句子的步骤(主语必须是同一个)
| 写两个同主语的简单句 | He turned off the radio. He left the room. |
| 去掉其中一个句子的主语 | 分析句子：他先关掉收音机， |
| 使用一个合适的介词合并为一句 | before、after |
| 介词后的动词变为动名词(介词后不能直接跟动词) |
|
doing 与having spent都是动名词，doing一般情况下表示的是主动或者正在进行。having spent 也是do+ing的形式，但他比普通的doing更高级，多了一层强调发生在之前的含义。这是因为having spent的原型是have spent现在完成时态变成的do+ing。所以都是doing但强调了发生在之前。
I have spent whole mornings on the river.I always go home with an empty bag. (after)
- After having spent whole mornings on the river, I always go home with an empty bag.
- I always go home with an empty bag, after having spent whole mornings on the river.
He sat there. He did not say anything. (without)
- He sat there without saying anythin.