49. He goes at 8 a.m. and es at 5 p.m. Today he is .
A. on duty; off duty; on night duty
B. on his duty; off the duty; on night duty
C. to duty; from duty; at night duty
D. in duty; out duty; at night duty
网友回答
(答案→)A. on duty; off duty; on night duty
B. on his duty; off the duty; on night duty
C. to duty; from duty; at night duty
D. in duty; out duty; at night duty
解析：可联系答.案.网客服索取。