哪种心脏瓣膜病变最易发生感染性心内膜炎,
A.主动脉瓣关闭不全伴心衰
B.重度二尖瓣狭窄
C.二尖瓣关闭不全
D.二尖瓣脱垂
E.二叶式主动脉瓣狭窄
参考答案:C
The prize will go to the writer ___ story shows the most imagination. [ ]
A. that
B. which
C. whose
D. what
随温度升高,压力容器的材质强度()十分明显。
A.升高
B.降低
C.变硬
D.融化