怪不得

      The adverb “怪不得” is used to indicate that one has realized the cause of a certain situation and therefore is no longer confused. It is often used as an adverbial in front of the subject-predicate construction, preceded or followed by sentences or phrases that indicate the cause, for example,

   下大雪了。怪不得这么冷。
   丁力波的妈妈是北京人，怪不得他的普通话说得这么好。 
   城里过春节没有农村热闹，怪不得很多城里人不是到外地旅游，就是到农村来过 节。
   怪不得他今天九点还没有起床，昨天晚上十二点他才从网吧回来。