充电式照明灯每半年应进行（）次充分放电。
A.1
B.2
C.3
D.4
参考答案：A
— She didn't come to school yesterday, did she?
— ______. Though she was not feeling very well. [ ]
A. Yes, she didn't
B. Yes, she did
C. No, she did
D. No, she didn't
信息处理程序的第一步工作是（）。
A、鉴别
B、筛选
C、整序
D、研究
