— You always spend only a little time on your study. You really me down.— I’m sorry Mum.

问题补充：

— You always spend only a little time on your study. You really me down.

— I’m sorry, Mum. I won’t do that again.

A. take

B. let

C. put

D. look

答案：

A. take

(答案→)B. let

C. put

D. look

解析：let sb down让某人很失望，固定结构。句意：——你总是只花一点点时间进行学习，真让我很失望。——对不起，妈妈。我再也不那样了。故选B