计算机在人工管理数据阶段，用来存储数据的是（）。
A.软磁盘
B.硬磁盘
C.纸带
D.光盘
参考答案：C
I was blessed with a happy childhood, ______ I really enjoy myself playing with my best friend Danny.[ ]
A. which
B. whose
C. when
D. where
反粒度过滤的基本原理？
