hesentafax.hewantedhismothertolearnthegoodnews.变成连句hesentafaxinorderthathismothermightlearnthegoodnews.或hesentafaxinorderthathismothershouldlearnthegoodnews.请问为什么要加上might或shoud这是

Question

he sent a fax.he wanted his mother to learn the good news.变成连句
he sent a fax in order that his mother might learn the good news.
或 he sent a fax in order that his mother should learn the good news.
请问为什么要加上might或shoud这是什么语法现象,不加 会怎么错

Answer 1

so that 表示的是将来的目的,还没有发生,所以用may,might或者will, would, shall,should这样的情态动词+动词原形来表达目的.祝你愉快.