We hope that we can _________ the world ________ wars, killers and everything else that is bad.

A．get rid of; by

B．be rid of; by

C．rid; of

D．get rid; of

二尖瓣关闭不全时出现的体征有（）

A.心尖部收缩期杂音

B.心脏杂音向左腋下传导

C.S1常减弱

D.心尖搏动向左下移位

E.常听到S3