不定式的时态

1. 一般时(to do)；

I begin to understand the truth.

Would you like to come to my birthday party?

Did you go to visit the Great Wall last year？

2. 现在时(to be doing)；

He seems to be following us.

I happened to be standing next to him when he fell to the ground.

The teacher happened to be correcting our papers when I came in.

3. 完成时(to have done)；

He seems to have caught a cold.

I'm sorry to have given you so much trouble.

I hope to have finished the work by now.

4. 完成进行时(to have been doing)；

He seems to have been waiting a long time.

He pretended to have been studying.

He was said to have been teaching in high school for 2 years.

不定式的被动语态

1. 不定式一般时的被动语态(to be done)；

Did it need to be done so soon?

She can't bear to be laughed at.

There was a lot of rubbish to be got rid of.

2. 不定式完成时的被动语态(to have been done)；

I'm pleased to have been given this opportunity.

The work seemed to have been finished before the deadline.

It's said to have been built in the Ming dynasty.