Mary
Mary --be in because i saw her in town only a hour ago A won't B mustn't may not D can't 选择什么并讲解
Mary __B__be in because i saw her in town only a hour ago A won't B mustn't C may not D can't 玛丽可能不在家，因为我一小时前在镇里看到了她. A won't：将来时，前后时态不一致，不用 B mustn't ：may的否定形式，意思是：不可能 C may not ：意思是：可以不 D can't ：意思是：不能，不会