心脏瓣膜病最常见的联合瓣膜损害是()
A.二尖瓣十三尖瓣
B.二尖瓣十主动脉瓣
C.主动脉瓣十肺动脉瓣
D.主动脉瓣十三尖瓣
E.三尖瓣十肺动脉瓣
参考答案:B
What a pity it is to have lost the game ______ one goal!
[ ]
A. for
B. by
C. over
D. to
安装水表时,水表前后直管段的长度有什么要求?