(1)—How about coming to my house?
—I’d love to if it doesn’t give you so much trouble.
在hope, like, love, promise, want, wish等词后作宾语的不定式常省略。再如：
You may go if you want to.
She can get a job if she hopes to.
—How about going hunting with me tomorrow?
—I’d like to, but I have no time.
(2)Don’t close the window until I ask you to.
在allow, ask, tell 等词后作宾语补足语的不定式常省略。再如：
Don’t touch the light unless your mother allows you to.
Don’t plant potatoes until the peasant tells you to.
(3)He didn’t want to hand in his composition, but he had to.
在be able to, be going to, have to, need to, enough to, used to等后的不定式需省略。再如：
I don’t sing much, now, but I used to a lot.
If you don’t want to say anything at the meeting, you don’t need to.
She didn’t go out last night, because she was afraid to.
在afraid, glad, happy, pleased, sorry等词后作状语的不定式常省略。再如：—Will you go with me to see the film tonight?
—I’ll be glad to.