轻型井点使用时，一般应连续抽水。正常的出水规律是(    )
A、先小后大，先清后浑
B、先大后小，先清后浑
C、先小后大，先浑后清
D、先大后小，先浑后清

A．mesh economy.
B．collaborative commerce.
C．we-commerce.
D．omni-channel commerce.

A．amiable
B．meager
C．retractable
D．diplomatic