慢性肺源性心脏病患者最常见的酸碱失衡类型是( )

A．呼吸性酸中毒

B．代谢性酸中毒

C．呼吸性碱中毒

D．代谢性碱中毒

For an OSV not on an international voyage，an approved substitute for an impulse projected type line throwing appliance is a（）.

A.spring-loaded line thrower

B.hand thrown buoyant line

C.shoulder type line throwing gun

D.heaving line