求教英语选择题,麻烦详解一下C选项

题目

求教英语选择题,麻烦详解一下C选项
Son:Father,you promised that if I did well in the exam you would buy me a new bike.
Father:________ I will buy it tomorrow.
A.So did I.x05x05x05x05x05
B.Really?
C.So I did.x05x05x05x05x05
D.You should keep your promise.

答案

这道题目考查的是so did i 与so i did的区别.如果是用前一个的话,表示是“我也是这样做的（暗含前面有人做过和他一样的事）,而第二个则是表示“我确实这样做的啊”