阴离子型表面活性剂为()。
A.十二烷基苯磺酸钠
B.卵磷脂
C.HLB7~9
D.苯扎氯铵
E.PluronicF68
参考答案:A
解析:
[知识点] 表面活性剂
— Cathy, I have cleaned the room for you.
— Thanks. You _____ it. I could manage it myself. [ ]
A. didn't need to do
B. needn't have done
C. mustn't do
D. shouldn't have done
为满足人员在建筑着火后能有多个不同方向的疏散路线的要求,一般要求建筑内的每个防火分区或一个防火分区的每个楼层,安全出口不少于()个。
A.1
B.2
C.3
D.4