WHEN I CAME TO VISIT HIM LAST NIGHT, HE __________ HIS HOMEWORK. H...

28. - KIEM TRA 1TIET SO 1 TRON 4 DE
KIEM TRA 1TIET SO 1 TRON 4 DE
28. When I came to visit him last night, he __________ his homework. He said that he __________ it since 6 o'clock.A. was doing/had been doing B. was doing/has been doingC. did/did D. was doing/was doing