The old professor has such a bad memory that he looks for the watch while he is .
A. having it on
B. having on it
C. wearing it
D. putting it on
网友回答
A. having it on
B. having on it
(答案→)C. wearing it
D. putting it on
解析：表示穿戴的意思时，用动词的进行时be wearing sth.， have on一般不用进行时。