--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
--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
D