美国根据不同的油井条件，选取不同的抽油方法，如对强水淹井，采用（）采油。
A、电泵
B、水力活塞泵
C、抽油机深井泵
D、气举法
参考答案：A
This job is great salary. However, it has several disadvantage, such as long working hours and inconvenient working place.
A．on behalf of
B．in addition to
C．thanks to
D．in terms of
放顶煤工艺通常采用（）。
A、一刀一放
B、两刀一放
C、一刀两放
D、其它
