英语语法，动词的非谓语形式，不定式的句法作用。除了构成谓语外，不定式在句中还可构成：
主语，宾语，表语，定语，状语
例如：To go or not to go is a question. 去还是不去是一个问题。（主语）
She decided to have a try. 她决定试一试。（宾语）
Her job was to answer questions.她的工作是回答问题。（表语）
I have a lot of things to do.我有很多工作要做。
She went to town to do some shopping. 她进城去买东西。
备注小贴士： 不定式作定语时，如果不定式动词为不及物动词，其后的介词不可省略。例如：I have only a cold room to live in. 我只有一间冰冷的屋子可以住。
不定式有时不带to: 例如：I saw a man enter the room. 我看见一个走进屋子。
有时还有被动(a),完成（b）及进行形式（e）: 例如：{a}, She likes to be praised.
{b}, Im sorry to have given you so much trouble. {c}, She seems to be talking with somebody.
