银行已全面使用十二级分类，与五级分类关联仅为了符合外部监管的需要。
参考答案：错
．Never_______Lisa would arrive but she turned up at the last minute.
A．did we think
B．have we thought
C．we thought
D．we have thought
设平流式沉淀池原长为L，池深为H，水平流速为v，颗粒沉速为u0，假定v，u0不变，H减为H/3，则L将为（）可达到与原池相同的去除率。
A.3L
B.6L
C.L/3
D.L/6
