A young man was called up for army service and had to go to be medically examined. The doctor (21) at a desk when he went (22) He said to the man, "Take your coat and shirt off, loosen(松开)your belt and sit on (23) chair."The young man did (24) The doctor looked (25) him for a moment without getting (26) from his chair and then said, “All right. (27) your clothes again” “ (28) you haven’ t examined me at (29) !" the young man said in a troubled (30) . “It isn’t (31) ,” the doctor said gently.” (32) I told you to take your coat and shirt off, you (33) me all right, so you aren’t (34) .You saw the chair I pointed (35) , so your eyesight’ s good enough (36) the army. You (37) to take your clothes off and to sit on the chair, so your body (38) be healthy, and you understood (39) I told you to do and did it without a (40) , so you must possess enough intelligence (智力) for the army." 31().

A. in
B. for
C. to
D. at