向上特高压直流输电工程中,无功功率控制功能位于()。
A.双极控制层
B.极控制层
C.换流器控制层
D.阀控制单元
参考答案:A
— I have come to say good-by.
— What time_____?[ ]
A. are you about to leave
B. are you leaving
C. do you leave
D. shall you leave
蛋白质初步消化的部位是 ( )
A.口腔
B.胃
C.小肠
D.大肠