作业帮英语中过去时的情态动词句型公式?要句型……是公式，不要句型
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/28 00:50:57
英语中过去时的情态动词句型公式?要句型……是公式，不要句型
英语中过去时的情态动词句型公式?
要句型……
是公式，不要句型
英语中过去时的情态动词句型公式?要句型……是公式，不要句型
情态动词+动词完成式即“情态动词+ have + done分词”,表示对过去行为或动作进行推测、评论或判断.
1.must have done
must have done 表示对过去某事的肯定猜测.其否定或疑问形式都用can(could) 来表示.
例如：
Since the road is wet,it must have rained last night.
He can’t have missed the way.I drew him a map.
“The dictionary has disappeared.Who could have taken it?”
当然对现在发生或将来发生的事情,要用must do 表示猜测,否定为can’t do.
He must understand that we mean business.
You must be hungry after a long walk.
2.may / might have done
may / might have done 表示推测过去某事“也许”发生了.may 比 might 表示的可能性在说话人看来稍大些.
例如：
I can’t find my keys.I may / might have left them at the school yesterday.
3.could have done 在肯定句型中,往往用作委婉的批评.本应该做什么,而没做; 有时也用作猜测.
You could have told us earlier.
Tom could have taken the dictionary.
4.ought to / should have done和 ought not to / shouldn’t have done
ought to / should have done 和 ought not to / shouldn’t have done 用于对已发生的情况表示“责备”、“不满”,
分别表示“本应该…”和“本不应该…”.例如：
1）With all the work finished,I should have gone to the party last night.
2）You ought not to have made fun of him.He is not the one you laugh at but learn from.
5.needn’t have done
needn’t have done 表示过去做了某事,但没有做的必要,意为“本没必要…”.例如：
You needn’t have waken me up; I don’t have to go to work today.
注：表示推测过去某动作发生的可能性时,就表示的可能性程度而言,must最大,could其次,may更次之,
might最小.例如：
“I wonder how Tom knew about your past.”
“He must / could / may / might have heard of it from Mary.”