_____is known to us all is that we should do as much as we can ______ stop the pollution of the environment.

A．It; help

B．What; to help

C．As ; to help

D．That ; help

国际收支出现大量顺差时会导致下列哪种经济现象。（）

A、本币汇率上浮，出口增加

B、本币汇率上浮，出口减少

C、本币汇率下浮，出口增加

D、本币汇率下浮，出口减少