做某事而实际未做。
You ought to have helped him (but you didn't)
书报的标题,小说等情节介绍常用一般现在时。
表示感觉,愿望和状态的某些动词如have,be,hear,see,like等词一般不用进行时。
有些动词形式上是主动结构,但表示被动的意思。常见的有可和 well, easily 等副词连用的不及物动词sell,wash,write,read,clean,cook等。例如：
The cloth washes well.这布很经洗。
The new product sells well.这新产品很畅销。
The pen writes well.这支笔很好写。
虚拟语气在动词 arrange,command, demand, desire,insist, order,propose, request, require, suggest等后面的宾语从句中用“(should)＋ 动词原形”。
例如：We suggested that we (should) have a meeting.
We insisted that they (should) go with us.
The doctor ordered that she (should) stay in bed for a few days.
He demanded that we (should) start right away.
注意:insist 作“力言”、“强调”解时,宾语从句不用虚拟语气。只有当 insist 作“坚持(认为),”“坚持(应该)”解时宾语从句才用虚拟语气。例如:
Mike insisted that he had never stolen anything.
作advice,idea,order,demand,plan,proposal,suggestion,request等名词的表语从句和同位语从句,其谓语动词要用虚拟语气的结构“(should)＋动词原形”。例如：We all agreed to his suggestion that we(should) go to Beijing for sightseeing.
My idea is that we (should) do exercises first.
在feel,hear,listen to,look at,notice,observe,see, watch,have,let,make等词后的补足语中,不定式不带to。但是这些句子如果变成被动结构时,就必须带to。例如：I often hear him sing the song. He is often heard to sing the song.
注意：不定式动词在介词but, except, besides后面时,如果这些介词之前有行为动词do的各种形式,那么,这些介词后的不定式不带to,否则要

上一页  [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]  ... 下一页  >>