___________ is the capital of China.
A:Shanghai
B:Guangzhou
C:Beijing
A.
B.
C.
D.
E.
F.
如图所示,右端封闭的U形管内有A、B两段被水银柱封闭的空气柱.若大气压强为p0,各段水银柱高如图所示,则空气柱A、B的压强分别为pA=____,pB=____.