问题补充：
Who is the man a blue shirt? I have never seen him before.
A. is wearing
B. dressed up
C. dressed in
D. worn
答案：
A. is wearing
B. dressed up
(答案→)C. dressed in
D. worn
解析：考查非谓语动词作定语，dress与man是被动关系，所以用过去分词，其中in后面经常跟什么样的衣服或者什么颜色的衣服。 dressed in修饰the man， man与wear是主动关系，所以答案D的正确形式应该是wearing。dress up是“打扮”的意思，与句义不符。答案A，
