HE WAS WORKING IN A FACTORY WHEN I MET HIM, ...HE HAD BEEN IN THE A...

Lớp 9 Tiếng Anh Đề thi tuyển sinh vào 10 môn Tiếng Anh (Chuyên), Sở GD TPHCM 2020-2021 (có kèm đáp án), môn Tiếng anh, lớp 9

3. He was working in a factory when I met him, ...he had been in the army. A. before which B. by when C. but then D. during which