资料1
资料3
资料4
请根据以上资料,选择以下栏目的正确选项:
“件数”栏:()。
A.74
B.20270
C.14
D.400
参考答案:C
什么是电源的外特性?
I()have watched that movie--it'll give me horrible dreams.
A. shouldn' t
B. needn' t
C. couldn't
D. mustn't