500 Câu trắc nghiệm tổng hợp ngữ pháp Tiếng Anh thi THPT Quốc gia (Phần 7)

She is tired because she ------------- all day

19/25

She is tired because she ------------- all day.

is studied

has been studying

had been studying

studied

Giải thích

Chọn B