我国家庭电路的电压是_____V，一节新干电池的电压是_____V，对于人体而言安全电压是_____V。

His business failure left him at the edge of desperation, but,         , he managed to go out of the shadow through years of efforts.

A．time and tide wait for no man

B．don’t count your chickens before they are hatched

C．no pains, no gains

D．time heals all wounds