叠置法将同比例的土地利用现状图与地形图、土壤图叠加，形成的封闭图斑即为有一定地形特征、土壤性质和耕地类型的定级单元。若图斑小于最小上图面积（）mm²，则应进行归并。

A.5

B.6

C.7

D.8

It is really difficult to ___ there few flats among so many people.

A．separate

B．divide in

C．separate up

D．divide up