问题补充：
. --So hard in the past few months that he has made great progress in English.
--I can see that, only a few mistakes he made in this exam.
A. he worked
B. did he work
C. he has worked
D. has he worked
答案：
A. he worked
B. did he work
C. he has worked
(答案→)D. has he worked
解析：考查倒装句。So +形容词或副词放在句首，使用部分倒装，根据题中in the past few months，可知应用现在完成时态，句意：在过去的几个月他如此的努力学习以至于他在英语方面取得了很大进步。我知道了，在考试中他只犯了几处错误。所以选D。
