两台流量不等的离心泵串联操作时，应把流量大的离心泵放置在（）。
A、排出端
B、吸入端
C、都可以
D、不能确定
参考答案：B
The reason_____he gave for his coming late was _____his car broke down on the way.
A．why;because
B．that;that
C．for which;that
D．that;because
刮大风的时候，在北半球纸屑（）
