She ……………. well at school but thatchanged when she became friends witha different group of girls.
A. did
B. had done
C. had been doing
Câu trả lời là: C là đáp án đúng
Công thức nguyên hàm và tích phân
She ……………. well at school but thatchanged when she became friends witha different group of girls.
A. did
B. had done
C. had been doing
Câu trả lời là: C là đáp án đúng