a) 作主语时，不定式多指具体的、一次性的动作，动名词多泛指概念性动作，在意义上较为笼统和抽象，含普遍意味。比如：
- To get there by bike will take us an hour.
- Learning from others is important.
b) 有些动词要求不定式作宾语。比如：
afford, agree, aim, apply, arrange, cause, consent, dare, demand, desire, determine, endeavor, expect, fail, hesitate, learn, manage, offer, ought, plan, plot, prepare, presume, pretend, proceed, profess, refuse, resolve, strive, struggle, swear, threaten, tend, volunteer, undertake, wait, want等。
c) 有些动词后要求动名词作宾语。比如：
acknowledge, admit, adore, advise, advocate, anticipate, appreciate, avoid, complete, confess, consider, contemplate, defer, delay, deny, discuss, enjoy, escape, evade, facilitate, fancy, favor, forbid, grudge, imagine, justify, mention, necessitate, postpone, prevent, quit, recall, recommend, renounce, regret, require, resent, resist, resume, risk, stand, suggest, tolerate, warrant等。
d) 在 can't bear, like, hate, prefer 等表示喜好的动词后，动名词表示一般倾向，不定式表示具体行为。比如：
- I would like to go with him.
- He really loves jogging before breakfast.
e) 在 bear, deserve, need, require, want 等动词后，动名词表示被动含义，不定式表示主动含义。比如：
- We want to think it over.
- This problem needs thinking about.
f) can not help but, rather than, sooner than, had better, other than 短语后接不带 to 的不定式。比如：
- He said he'd sooner die than betray his friend.
g) 介词后一般使用动名词作宾语，不用不定式；但是在介词 but, except, save 后接不定式作宾语，同时，若前面有 do anything/nothing/everything 结构时，其后接不带 to 的不定式作宾语。比如：
- He wanted nothing but to stay there.
- They did nothing but complain.
a) 现在分词的一般时表示主动的、正在进行的动作；过去分词的一般时表示被动的、已经完成的动作。分词短语作定语时，逻辑主语为它所修饰的名词；分词短语作状语时，逻辑主语必须和主句主语保持一致。比如：
- There is not much work finished.
- He stood by the window, reading a book.
b) 表示已经完成的主动的动作，使用现在分词的完成时。比如：
- Having finished his homework, Tom went out to meet his friends.
c) 表示正在进行的被动的动作，使用现在分词的一般被动式。例如：
- This is the question being discussed.
d) 表示已经完成的被动动作，既可以用现在分词的完成被动式，也可以用过去分词，但是前者只作状语，不可作定语，而后者作定语、状语均可。比如：
- The stolen car was found by the police last week.
- Having been praised a second time/Praised a second time, I decided to make still greater progress.
e) 当分词有独立主语（不同于主句主语的名词或代词）时，则是一种独立主格结构形式。比如：
- The bell ringing, we all stopped talking.（=When the bell rang, we all stopped talking.）
- There being no bus, we had to walk home.（=There was no bus, so we had to walk home.）
f) 现在分词 being 在独立主格结构中往往被省略。比如：
- He came into the room,his face(being)red with cold.
a) 动词不定式可以作目的状语，分词不可以。比如：
- He got up at 6 a.m. to catch the earliest train.
b) 现在分词可以作结果状语，但是在 so...as to... 、 such...as to... 、 ...enough to... 等结构中需用不定式作结果状语。比如：
- They all went out, leaving the 5-year-old Tom to stay at home alone.
- He is not so silly as to do such thing.
c) 不定式 to find, to see, to learn 等通常表示意外的结果，前面可以加上 only 突出不愉快。比如：
- He woke up, only to find himself in a dark room.
d) 分词短语可以作时间状语和伴随状语，不定式则不可以。比如：
- They came out of the classroom, laughing and chatting.（伴随状语）
- When asked to speak, he complained about the poor service.（时间状语）
