批复文种的源头是()。
A.复
B.批答
C.函
D.报
E.公函
参考答案:A, B
Since the energy crisis, these big cars have become a real liability. They cost too much to run.()
A. lack of reliability
B. substitute
C. costly means of transport
D. disadvantage
请简述发电机不发电的原因。