By making friends with the native speakers, one can _________ a lot of their language.

A．take up

B．set up

C．pick up

D．put up

前置胎盘时 * * 流血特征是

A．无痛性 * * 流血

B．有痛性 * * 流血

C． * * 流血常与外伤有关

D．宫缩时 * * 流血停止

E． * * 流血量与贫血程度不成正比