画出电动截止阀、止回阀、气动调节阀在汽水系统图上的表示方法。
参考答案：
暴发类型不包括（）
A.混合型
B.连续传播性流行
C.同源暴发
D.污染型
E.先同源暴发，再暴发连续传播流行
Some people said _____ that Copenhagen Conference 2009 didn't reach any official agreement. [ ]
A. what was a pity
B. what a pity it was
C. how pity was it
D. it was what a pity
