分类：教育/科学-外语学习
问题：关于情态动词的3道英语选择题1.Loudspeakerswere 
1.Loudeakers were fixed in the hall so that everyone _____ an opportunity to hear the speech.A.ought to have B. must have C.may have D.should have答案选择C.为什么不能选D呢?谢谢2.He spoke slowly so that everyone _____ what he said.A.ought to understand B.should understand C.may unde1.Loudeakers were fixed in the hall so that everyone _____ an opportunity to hear the speech.A.ought to have B. must have C.may have D.should have答案选择C.为什么不能选D呢?谢谢2.He spoke slowly so that everyone _____ what he said.A.ought to understand B.should understand C.may understand D.must understand答案为B.为什么C不行呢？3.We did hold a meeting yesterday, but you _______ , so we did not inform you.A. did not need attending   B.needn't have attendedC. did not need to attend   D.needn't attend正确答案C.D为何不对？need作为情态动词使用不就相当于C吗？ 
回答：1。D是should have done 固定用法。是本来应该做而没有做的事情
而在这个题中，may have 表示可以干什么。。。。
本题目的意思是
扬声器固定在大厅里，是让大家有机会听到讲话。


2不懂，。。
不行就凭语感

3 need 可以做情态动词和实义动词
在C中是用做实义动词
而本句有but 连接，
前后要一致