當(dāng)要用動(dòng)詞相關(guān)的動(dòng)作作主語時(shí),動(dòng)詞要用+ing形式.
Smoking is bad for your health.
用動(dòng)詞原形的幾情況
1.加助動(dòng)詞do,does或did 的肯定句變成否定句時(shí),其后面的動(dòng)詞要用動(dòng)詞原形；
He didn’t work hard at English last term.
2.情態(tài)動(dòng)詞后面要用動(dòng)詞原形；
Must I be at home tonight?
3.be going to,will,shall 等構(gòu)成的將來時(shí)態(tài),其后面的動(dòng)詞要用動(dòng)詞原形；
There will be on a new interesting film at the cinema.
4.祈使句要用動(dòng)詞原形；Be careful,Lin tao!
5.let開頭的祈使句,其后面的動(dòng)詞要用動(dòng)詞原形；
Let’s have a look at the pictures.
6.had better 后面要用動(dòng)詞原形；
you’d better put on more clothes.It’s very cold outside.
7.why not 之后要用動(dòng)詞原形；
Why not come a little earlier?= Why don’t you come a little earlier?
8.動(dòng)詞不定式to之后要用動(dòng)詞原形；
Please give me something nice to eat.
9.feel,hear,see,watch 等感官動(dòng)詞之后要用動(dòng)詞原形.如果表示這一動(dòng)作正在進(jìn)行,就用現(xiàn)在分詞.
Sometimes we can hear a girl sing in the room.
I feel my left leg hurting badly.
表示目的時(shí),一般用不定式 to do開頭.