动词不定式形式
1) 现在式：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) 完成式：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)进行式：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)完成进行式：
She is known to have been wreaking on the problem for many years.
一般在表示情绪的动词后加to do也表将来