题目内容：

When Mr Green got to the entrance of the hall,he saw some kids ____ there.
smoke,为什么不用smoking,请解析.
The problem is _____ difficlt for us____.
a.so;work out b.very too;to be worked out c.rather too;to work out d.quite too;to work it out
请问为什么?
在此先谢了.
Don't write ___ your pencil .Please write ____ pen.
a.with;with b.with;in
为什么？

优质解答

第一题答案错了,不存在see sb. to do sth.的形式,see sb. do sth中的do是不带to的动词不定式,不应该用过去式或者其他形式的.类似的还有:watch sb do sth,let/make/have sb do sth,在英语中有10个半动词可以跟不带to ...