Before examination our teacher always asked us to _____ what we have learned. [ ]

A. go back

B. go through

C. go off

D. go over

某建筑采用天然地基基础埋深1.5m，设防烈度8度，土层分布：0～7m黏土，可塑，f_ak=180kPa，7～12m细砂，稍密，地下水位在地面下6m，判别砂土的液化可能性。（）

A.液化

B.不液化

C.轻微液化

D.无法判别