问题:
He set_________ at about 9 o"clock.
[ ]
A. about to work
B. about to working
C. about working
D. out working
He set_________ at about 9 o"clock.
B. about to working
C. about working
D. out working
[ ]
A. about to work B. about to working
C. about working
D. out working
参考答案: