Question

It's necessary that she help him。如果是过去的话，能不能说成It's necessary that she should have helped him.

Answer 1

问：It's necessary that she help him。如果是过去的话，能不能说成It's necessary that she should have helped him.

答：It's necessary that she help him。如果是过去的话，能不能说成可以但是你的语句时错误的哈It's necessary that she should have helped him.

答：完成时态

答：It's necessary that she help him。如果是过去的话，要表示成It's had necessary that she should have helped him. 语法，完成时态，had done should have done

问：老师，你的也是错误的吧

问：怎么可能is 放在had前面

答：It's necessary that she help him。如果是过去的话，要表示成It had necessary that she should have helped him. 语法，完成时态，had done should have done

答：这样没删着

答：你就记得一个语法

答：无论是选择还是填空都用他

问：那有没有一种说法是It's strange that you should make a mistake

答：这句话是对的意思是It's strange that you should make a mistake，很奇怪你会犯下这样的错误

问：能不能这样说

问：那这里 it is是真实语气啊为什么你那个要改成hadbeen

答：因为你上面那句话把后面加了should have l了呀，变成虚拟语气

答：就是因为后面变了所以才会这样的哈

答：It's necessary that she help him。翻译是，她帮助了他是很有必要的如果是过去的话，It's necessary that she should have helped him.这句话意思是她应该帮助他是很有必要的，啊是虚拟语气

答：主句与if条件句中的动作都发生在过去时,主句谓语动词就要使用had done形式,if条件句中谓语动词则要使用would have done形式 。e.g.If I had worked hard,I would have passed all the exams.当主句以及if条件句中的动作都发生在现在时,主句的谓语动词必须使用did(be动词用were),if条件句动词须使用would do形式。e.g.If he came on time for the meeting,I would treat you to a rich meal.If I were you,I would go with him.当主句和if条件句的动作都发生在将来时,主句动词可以使用did,should do 或were to do形式,if条件句中动词须使用would do形式.e.g.If you kept/should / keep were to keep your promise,you would earn more than trust.