The book is difficult to understand. There are lots of letters to write. I don't know what 1o do next.
He has a large family to support. The box is too heavy to carry
(五)作状语
1. 不定式常作目的状语、结果状语和原因状语。作目的状语不定式作目的状语时前面可以加 in order或so as,构成in order to do或so to do结构。 in order to do可放在句首,也可放 在句中 ,so as to do只能用于句中
He took down my telephone number in order to/so as to remember it.
3,有些动词后,作宾语补足语的动词不定式省略to.常见的这类词 有see, hear, watch, feel, make , have, let等。
The joke made us all laugh.
but + (to) do 结构
1.连词but意为“除 …之外”中情势时, but后的不定式要省去to,否则要带to.
I'm glad to meet you.见到你我很高兴
(六)作补语
1,下列动词常用不定式作宾补:advise, allow, ask, beg, encourage, expect, force, invite, order, persuade, require, teach, tell, want, warn等。
动词不定式
进行式 主动情势: to be doing/ not to be doing