污水中污染物类型数=1，需预测其浓度的水质参数数目＜7，这类污水水质的复杂程度属( )。
A．复杂
B．中等
C．简单
D．一般
参考答案：D
– Miss Smith never wastes money on anything too expensive, even though she can ________ to.
– Yes, she does. She has given much of her money to charities.
A．allow
B．pay
C．afford
D．send
客运列车脱轨2辆以上18辆以下为（）。
A、特别重大事故
B、重大事故
C、较大事故
D、一般A类事故
