动词不定式是英语非谓语动词的重要组成部份，结构：to + verb。其中：to 不是介词，是不定式符号。在句中可充当主语、补语等。举例如下：

1、主语：To be or not to be, this is a question exactly.

2、宾语：The project aims to provide an outlet for children's creativity.

3、定语：He's a pleasant fellow to work with.

4、状语：He went to Paris to learn French.

5、补语：The moter is made to run by electricity.