What's the matter? You look sad你怎么了？显得这么伤心

今天的几个句子是有关担心、惦念的：1.What's going on? 到底怎么回事？2.What are you worried about? 你担心什么？3.You look grave. 你今天看上去很悲伤。4.You look sad today. 你今天怎么满脸的不高兴。