Choose the best answer to complete the sentence below.
The teacher _______ before we arrived.
will leave
was leaving
has left
had left
Cấu trúc: S + had + Ved/ V3 before S + Ved/ V2
Cấu trúc: S + had + Ved/ V3 before S + Ved/ V2
=> The teacher had left before we arrived.
Tạm dịch: Giáo viên đã rời đi trước khi chúng tôi đến.
Đáp án : D