图a所示二端口网络NA的外特性如图B所示，NA的等效电源模型为（）。
A.
B.
C.
D.
参考答案：A
根据句意及首字母或中文提示补全单词。
1. The story is not interesting, and it is really b
2. He （睡觉）very late last night.
3. What is the w like today?
4. I have no work today. I am having a day o
5. （幸好）, he didn't hurt himself in the traffic accident.
