| 时态/语态 | 主动 | 被动 |
| 一般式 | to do | to be done |
| 进行式 | to be doing | |
| 完成式 | to have done | to have been done |
| 完成进行式 | to have been doing |
1） 现在时：一般现在时表示的动词，有时与谓语动词表示的动作同时发生，有时发生在谓语动词的动作之后。
He seems to know this.
I hope to see you again.
= I hope that I'll see you again.
我希望再见到你。
2） 完成时：表示的动作发生在谓语动词表示的动作之前。
I'm sorry to have given you so much trouble.
He seems to have caught a cold.
3） 进行时： 表示动作正在进行，与谓语动词表示的动作同时发生。
He seems to be eating something.
4） 完成进行时：
She is known to have been wreaking on the problem for many years.