--How often do you attend the evening classes?
--- , three times per week.
A. On the whole
B. On average
C. Little by little
D. In all
网友回答
A. On the whole
(答案→)B. On average
C. Little by little
D. In all
解析：短语辨析。 A整体来说； B. 普通，通常； C. 逐渐地 D.总共，合计。句意：你多久上一次夜校课程？——通常每周三次。故选B。