非谓语动词包括动词不定式、动名词、现在分词和过去分词，它们在句子中不作谓语，但可承担多种语法功能。以下是其用法总结:

1.动词不定式(to +动词原形)
①作主语:表具体动作，常用“it”作形式主语， 如"To learn English well is important."→
"It is important to learn English well."
②作宾语:常接不定式的动词有want， hope, decide, plan, agree, refuse, promise, manage, afford, learn等，如
" want to go to the park."
③作表语:说明主语的具体内容，常表目的或理想，如
"My dream is to become a doctor."
④作定语:修饰名词，表“未做的动作”，如
"l have a lot of wor to do."
⑤作状语:表目的、原因、结果，如
"He got up early to catch the bus."(目的)、
"She was happy to get a gift."(原因)、
“He lived to see his dream come true."
(结果）
⑥特殊形式:
to be doing (表动作正在进行)、
to have done(表动作已完成)、
to have been doing (表动作持续至今)。

2.动名词(动词+ ing)
①作主语:表抽象动作或习惯，如
"Swimming is good for health."
②作宾语:常接动名词的动词或短语有
enjoy， finish, avoid, suggest, mind, practice, be used to, look forward to, can't help等，如"She enjoys reading novels."
③作表语:说明主语的性质，如
“His hobby is collecting stamps."
④作定语:修饰名词，表用途，如
“a sleeping bag” (睡袋=a bag for sleeping)。
⑤注意:
stop to do(停下来去做另一件事)与
stop doing (停止正在做的事)意义不同。

3.现在分词(动词+ing)
①作定语:表主动、正在进行，如
“a running rabbit"(奔跑的兔子)。
②作表语:主语具某种特性，常修饰物，如"The movie is exciting."
③作宾补:感官动词(see, hear, watch, notice等)后接doing，表动作进行中，如
“I saw him crossing the road."
④作状语:表时间、原因、伴随，逻辑主语为主句主语，如
“Hearing the news, he became excited."
(- when he heard the news)

4.过去分词(动词的过去分词形式)
①作定语:表被动、完成，如
"the book written by Mo Yan".
②作表语:主语处于某种状态，常修饰人，如"He felt interested in gardening."
③作宾补:宾语承受动作，如
"She found her carrot stolen."
④作状语:表原因、条件、让步，逻辑主语为主句主语(被动关系)，如
"Seen from the hil, the field looks beautiful." (- because it is seen...).

易错点:
①不定式在使役动词(make, let, have)和感官动词(see,hear, watch等)后作宾补时，主动语态中省略to，被动语态中需还原to。
②动名词的逻辑主语常用物主代词或名词所有格，如"l appreciate your helping me."
③分词作状语时，逻辑主语需与主句主语一致， 否则需用独立主格结构。//@詠恆烛邩:非谓语动词咋用啊？