动词不定式在句中可充当主语、表语、宾语、宾补、定语和状语等。
一、作主语
动词不定式作主语可位于句首。例如:
To learn a skill is very important for everyone in society.
也可使用it作形式主语,而将其置于句末。例如:
It is necessary for young students to learn a foreign language.
动词不定式作主语的常用句型有:
1. It is+adj./ n. (+for sb./sth.) + to do sth.