WE ……… A VERY HARD LESSON THE DAY BEFORE YESTERDAY A. STUDIED ...

17. - BAI TAP CAC THI TIENG ANH 60 DAP AN
BAI TAP CAC THI TIENG ANH 60 DAP AN

17. we ……… a very hard lesson the day before yesterday

a. studied         b. have been studying

c. have studied      d. will study