左心功能不全由代偿转变为失代偿的表现是()
A.双肺出现湿啰音
B.第三心音奔马律
C.出现心房颤动
D.劳力性呼吸困难
E.夜间阵发性呼吸困难
参考答案:D
To learn the piece of music quickly, you'd better hear it ___ as many times as possible.
A.play
B.playing
C.played
D.to play
RNl系列熔断器是否熔断应根据()来判断。
A.熔断指示器
B.电路中电流表指0
C.电路中电压表指O