问题
选择题
He has been working hard day and night, which, of course, his tiredness.
A．accounts for
B．answers for
C．applies for
D．stands for
答案
答案：A
这题考查词义辨析：account for是…的原因，answer for为…负责，apply for申请，D. stand for代表，句意是：他白天黑夜的努力工作，这当然是他疲劳的原因了。选A。