Question

有两道不太明白的英语题，求大神讲解

1.Mrs Smith didn't come last night,did she?No,we ——for her.A whole night was wasted.A.couldn't have waited B.mustn't have waited C.didn't need to wait D.needn't have waited
答案是D，我想选C，为什么不行呢？
2.Every summer,the beautiful town welcomes top buskers,or street performers,____they're called ,from all over the world. A.as B.that C.which D.what 答案是A，为什么C不可以呢？
求解

Answer 1

needn't have done的意思是“本不需做而做了某事”，是一个固定搭配

as引导状语状语从句，修饰top buskers,or street performers整个句子，而which在这种情况只能做定语从句，而且只能修饰street performers