固定床的优点有()。
A、设备简单、操作方便;
B、对各种水质适应性强,出水水质较好;
C、树脂用量小,利用率高;
D、再生和清洗时间短。
参考答案:A, B
I admired my classmate Lisa very much. _____ her prettiness, she was smart and helpful.
A.Apart from
B.Except for
C.But for
D.In spite of
单筒岩心累计长度是指本层顶界距本筒岩心底界的长度。()