—________are they doing?
—They're running.[ ]
A. Who
B. How
C. What
D. Where
答案:C
每木调查
制作洋葱鳞片叶内表皮细胞临时装片时,首先要在洁净的载坡片中央滴一滴 ( )
A.清水
B.生理盐水
C.碘液
D.酒精