反映计算机存储容量的基本单位是（）。
A.二进制位
B.字节
C.字
D.双字
参考答案：B
- I came to your home yesterday afternoon, but nobody was in.
- Oh, we ________ some shopping in the supernarket. [ ]
A. have done
B. did
C. were doing
D. are doing
