循环水系统管线水冲洗一般使用（）。
A、脱盐水
B、消防水
C、新鲜水
D、循环水
参考答案：D
In the survey they listed twelve kinds of food _______would affect the work of the brain．
A．which the experts believed
B．that were believed
C．the experts believed that
D．the experts believed
Zeta电位降低产生：
A．分层B．转相C．酸败D．絮凝E．破裂
