在复吹转炉冶炼过程中选择底吹供气强度的根据是（）。
A．钢种
B．铁水成分
C．脱碳速度
参考答案：C
I always remember what she ______ when I saw her for the first time. [ ]
A. does
B. is doing
C. was doing
D. has done
