蒸发水冷器突然不上水或下水不稳的原因（）
A、水池水位低
B、系统真空度低
C、水泵上水少或跳闸
D、气压不稳
参考答案：A, C
I know a lot about football. Now I want to learn _____ about it. [ ]
A. many
B. some
C. more
望柱是古建筑栏杆设在每段（）之间的立柱。
