自动采样用自动采样器进行,有时间比例采样和流量比例采样。其中时间比例采样适用于
A、污水浓度较稳定时
B、污水排量较稳定时
C、污水流速较稳定时
D、以上均不对
参考答案:B
The new student was very slow to __________ the unusual rules of the school.
A.adapt for
B.adapting for
C.adapt to
D.adapting to
下列多项式能用平方差公式分解因式的是( )
A.4x2+y2
B.-4x2-y2
C.-4x2+y2
D.-4x+y2