I________at the checkout when I______a strange-looking man. A. was waiting/had noticed B. was waiting/noticed C. waited/was noticing D. waited/noticedĐoạn văn35/40I________at the checkout when I______a strange-looking man. was waiting/had noticed was waiting/noticed waited/was noticing waited/noticedGiải thíchĐáp án đúng là B. was waiting/ noticed