2015年职称英语考试已经开始备考，本阶段应该多整理一些基础词汇和语法。为此，网校特整理了“2015年职称英语考试语法知识”供您参考，希望对您有帮助！

不定式的时态和语态

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.