若xn=2,yn=3,则(xy)3n等于( )
A.12
B.16
C.18
D.216
(xy)3n=[xn•yn]3=(2×3)3=216.
故选D.
The farm ________ we see today is no longer the one ________ it was ten years ago. [ ]
A. that; that
B. where; that
C. where; where
D. which; which
将液体外加剂先与水混合,然后与其他材料一起拌合的方法称为先掺法。