题目内容：

Mrs Smith made a phone call to my mother yesterday evening.But she_______(not,be)in.
Mrs Smith made a phone call to my mother yesterday evening,but she_______(not,be)in.怎么填?为什么?
为什么不用didn’t?

优质解答

由于but后应跟一个完整的句子.
而did作为助动词不能代替谓语,故句子中仍缺少谓语.
所以要用be动词,be动词可以充当谓语.
故答案为wasn't