英语问题Whydidn'tSusancometoseeusyesterdayasshepromised?AShemustbebusyBShemighthavebeenfreeCShemusthavebeenbusyDShecan'tbefree为什么选C,能解释一下嘛~~~~~~~~~~~~~~~~~

Question

英语问题
Why didn't Susan come to see us yesterday as she promised?
A She must be busy
B She might have been free
C She must have been busy
D She can't be free
为什么选C,能解释一下嘛~~~~~~~~~~~~~~~~~

Answer 1

选C.
1.句子意思:问:为什么Susan没有遵守诺言过来看我们?
答:她一定是因为太忙了.(所以才没过来看我们)
所以,选象表达的是"对过去发生事情的肯定猜测".
2.了解一个句型:
must have done :一定是...或肯定是
(表示对过去事实的猜测\看法)
He must have ever been here.他一定到过这里.(猜测)
3.
类似的句型有:
could have done:本来可以做...(但没有做)
例:You could have killed me.你本来可以把我杀了.(但你没这样做)
should have done:你应该做...(但没有做)
4.关于must have done的例句:
He must have done it last night,didn't he?
他昨天晚上一定做了那件事情,不是吗?