液位控制系统组成（）.
A、调节阀
B、浮筒
C、液位探头
D、U/P阀
参考答案：A, B, C, D
I have two bicycles, ____ is made in Guangzhou;____ is made in Shanghai.
A．One…another
B．The other…one
C．One…the other
D．One..the others
