动词的非谓语形式做主语或表语
1. 一个简单句中只能有一个谓语动词，再出现动词要变成非谓语结构，to+v或v+ing或v+ed。
My parents wanted him work hard. work前面应该加to, work hard 作wanted 的宾语补足语，want 后常接不定式做宾补。
I remember saw him that day. 改成remember seeing remember 后加动名词做宾语。
I saw him walked into the building. walk see somebody do someting.
2. 对于taste, smell这些词，不能单纯看他们与食物是被动关系，要看实际原型句子中的关系是否为被动。
3. 非谓语动词：动名词，现在分词，过去动词，动词不定式
A. 动名词？？：具有名词功能
Being exposed to sunlight for too much time will do harm to one’s health. 动名词的被动形式做主语
B. 现在分词：主动和正在进行，经常性的
C. 过去分词：被动和已经完成
D. 动词不定式：表将来具体某一次
To save money now seems impossible.
4. It 作形式主语，后面常用不定式做真正的主语，或者动名词。
It is easy to learn English well.
nice, good, enjoyable, worthwhile, useless等形容词有用不定式也有动名词做主语的，what 在问句中作主语时，常用动名词短语来回答。
It is useless doing that.
5. What Yang Liwei wanted to do when he got out of the spaceship was share the joy with all Chinese.
I think the best thing you should do is look for another job.
动词不定式做表语时，如果前面有实意动词do的形式，作表语的不定式常常省略to。