Tim started studying Pascal two years ago.Đoạn văn49/50Tim started studying Pascal two years ago.Tim hasn’t started studying Pascal for two years.Tim has studied Pascal for two years.It’s two years since Tim has studied Pascal for two years.Tim has been studying Pascal two years ago.Giải thíchTạm dịch: Tim bắt đầu học Pascal từ hai năm trước.Giải thích: Bthì (QKĐ -> HTHT)