My English teacher gave us a suggestion yesterday, _____is often the case, ______ our monitor organize a debate after class.

A．which, which

B．which, that

C．as, that

D．as, which

确定基础底面积的根本原则是______。

A．基底单位面积压力大于地基承载力
B．基底单位面积压力小于地基承载力
C．基底单位面积压力等于地基承载力
D．基底单位面积压力不等于地基承载力