to do 是一般将来式,是打算去做什么 ；doing 是现在进行式,是现在正在做什么，也有例外，具体情况具体分析。
A. 跟不定式（to do）作宾语的动词：
want, wish, hope, manage, pretend, decide, learn, agree, expect, demand, long, ask, care, choose, dare, fail, offer, plan, prepare, promise, refuse, desire, happen, appear, intend, would like to, be said to;
B. 跟动名词(doing)作宾语的动词：
suggest, admit, finish, avoid, mind, enjoy, delay, practice, excuse sb. for, advice, consider, escape, miss, risk, dislike, imagine, permit, require(表被动), appreciate(感激)，understand, insist on, look forward to, get down to, devote oneself to, prefer…to… object to (反对), put off, apologize to sb.
for, give up, forgive sb. for, be worth, be fond of, be good at, be slow in, be active in, be afraid of, be tired of, be busy, succeed in, prevent/stop/keep sb. from, spend time (in), have difficult/trouble in, It’s no use/good, be pround of, instead of.
C. 跟动名词(doing)和动词不定式（to do）均可的词，含义无区别：
start, begin, continue, prefer, like, love, hate, 后跟to do 表具体和特定的动作， 后跟 doing 表泛指的动作
D.感官动词 + doing/to do
感官动词 see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do 表示动作的完整性，真实性；+doing 表示动作的连续性，进行性
例子：
I saw him work in the garden yesterday.
昨天我看见他在花园里干活了。(强调"我看见了"这个事实)
I saw him working in the garden yesterday.（强调"我见他正干活"这个动作）
昨天我见他正在花园里干活。
动词不定式由to加动词原形构成，也就是to do，它在句中可以作主语、宾语、表语、定语、状语、宾语补语、主语补语等，具有名词、形容词和副词性质。
动名词由动词原形加词尾-ing构成，也就是doing，它在句中可以作主语、宾语、表语、定语、宾语补语、主语补语等，具有名词性质。它们之间的区别如下。
一、作主语和表语：
动名词作主语和表语的时候表示事物化和抽象化的概念，不定式着重的是某次具体的动作。当动名词短语或不定式短语较长的时候，可以用it作形式主语。
二、作宾语：
动名词作宾语时强调一般情况，不定式强调某种具体情况。
