配置浓盐酸、浓硝酸，必须在（）中进行。
A、实验台
B、走廊
C、通风厨
D、门口或窗口
参考答案：C
When I met him the other day, it was the first time we ____ each other since we were at school. [ ]
A. saw
B. had seen
C. were seeing
D. have seen
高速计数功能占用的硬件（外部）端子有（）。
A.X0
B.X1
C.X2
D.X3
