It was the old clock that the old man spent the whole morning at home.
A. repair
B. repairing
C. to repair
D. in repair
网友回答
A. repair
(答案→)B. repairing
C. to repair
D. in repair
解析：
本题仍考查的是强调句型。该句可还原为：The old man spent the whole morning at home (in) repairing the old clock。故选B。