单选题 There is a______look on his face. What's on his mind?

【正确答案】 B
【答案解析】[解析] 此处需要一个修饰语，排除A和D(不正确)；B意为“忧虑的”相当于anxious；C意为“令人担心的”。所以答案为B。句意为“他脸色忧郁，有什么心事?”