下列有关海水综合利用的说法正确的是 [ ] A．利用电解的方法可以从海水中获取淡

《凡尔赛和约》签订后，法国司令福煦脱口而出：“这不是和平，这是二十年的休战”，验证这一预言的是[ ]

A．萨拉热窝事件

B．五四运动

C．一战全面爆发

D．二战全面爆发

When I try to understand ______ that prevents so many Americans from being as happy as one might expect, it seems to me that there are two causes.

A．why it does

B．what it does

C．what it is

D．why it is

合力总比分力大。[ ]

作图题：画出对称负荷的三相线电压和相电压的相量图。

有压管道的管径与管流水力半径的比值D/R=（）

A.1

B.2

C.8

D.4