关于人体内的血浆、组织液和淋巴三者之间的物质联系的表达，正确的是[ ]
A．
B．
C．
D．
答案：C
The wounded policeman ____though doctors made every effort to save him.
A．died
B．had died
C．killed
D．has been dead
YD5123-20109.0.6-6规定：井下作业时防止（）
A.中毒
B.有毒气体
C.甲烷
D.煤气
