—No, they ______.
A:Are; aren't
B:Do; aren't
C:Are; don't
D:Do; don't
一个长方体玻璃缸,从里面量长20厘米,宽15厘米,高12厘米.缸里装有水,把一个棱长6厘米的正方体石块放入水中(完全浸没),水面将升高多少厘米?
已知复数z=a+bi(a,b∈R且ab≠0),且z1-2i为实数,则ab=( )