John smoked cigarettes when he was a young man. => John used ….
John smoked cigarettes when he was a young man. => John used ….
Đáp án: John used to smoke cigarettes when he was a young man.
Giải thích: used to Vinf: đã từng có thói quen gì
Dịch: John từng hút thuốc lá khi còn trẻ.