以下选项符合图标含义的是（）
A.当心感染
B.当心中毒
C.当心触电
参考答案：A
肺Ⅱ型细胞合成的肺泡表面活性物质的重要作用是()
A．促进中性粒细胞聚集
B．使肺泡萎陷
C．促炎作用
D．肺泡表面张力调节
E．增加肺组织弹性
The United Nations Conference on Drug Abuse, which took place earlier this year in Vienna, was a very ______ meeting.
A．productive
B．overwhelming
C．compulsory
D．protective
