I read / was reading a book about Charles Dickens while my sister watched / was watching a documentary about Karl Marx.
I read / was reading a book about Charles Dickens while my sister watched / was watching a documentary about Karl Marx.
Hai hành động đang diễn ra song song → cả hai dùng quá khứ tiếp diễn.
Dịch: Tôi đang đọc một cuốn sách về Charles Dickens trong khi em gái tôi đang xem phim tài liệu về Karl Marx.