管涌险情抢护时，围井内必须用( )铺填。
A．砂石反滤料 B．土工织物C．透水性材料 D．不透水性材料
参考答案：C
— Mr. Smith has got a very good job in the famous company.
— ________ he looks so happy. [ ]
A. It's certain
B. That's because
C. No doubt
D. No wonder
下列疾病，不出现肝颈静脉回流征的是（）
A.缩窄性心包炎
B.上腔静脉阻塞综合征
C.右心衰竭
D.心包积液
E.肺心病
