PTSD可以出现（）
A.闪回
B.回避
C.警觉性增高
D.心理麻木
E.情绪高涨
参考答案：A, B, C, D, E
There were ___________ white clouds in the sky. [ ]
A. too many
B. too much
C. much too
确定闭式喷头的动作温度，一般要求喷头的公称动作温度比环境最高温度高30℃。（）
