I saw a bad traffic accident yesterday while I was going to school. I _______ (walk) along the High Street when I ________ (hear) a loud noise. Then someone said, 'That car crashed into a bus while it ______ (turn) the corner!' It was a real emergency. People _______ (get) off the bus quickly when a fire engine _____ (arrive). The firefighters stopped the fire in a few minites and everyone was safe. An ambulance _____ (come) while they ________ (fight) the fire. It took two people to hospital. A reporter came to write about it. 'What ________ you ________ (do) when the accident happened ?' she asked me. 'I ______(wait) to cross the road,' I answered.

I saw a bad traffic accident yesterday while I was going to school. I __was walking (when)_____ (walk) along the High Street when I ____heard (when)____ (hear) a loud noise. Then someone said, 'That car crashed into a bus while it ___was turning (while)___ (turn) the corner!' It was a real emergency. People ____were getting (when)___ (get) off the bus quickly when a fire engine __arrived (when)___ (arrive). The firefighters stopped the fire in a few minites and everyone was safe. An ambulance __was coming (while)___ (come) while they ___were fighting (while)_____ (fight) the fire. It took two people to hospital. A reporter came to write about it. 'What ___were_____ you ___doing (when)_____ (do) when the accident happened ?' she asked me. 'I ___was waiting (trả lời cho câu hỏi trên)___(wait) to cross the road,' I answered.

Cấu trúc: S + was/were + V-ing + .....+ When+ S + V (quá khứ)

Diễn tả 1 hành động đang xảy ra mà cs 1 hành động khác xen vào

Cấu trúc : S+ was/were + V-ing +....+ while + S + V(quá khứ)

Diễn tả 2 hành động xảy ra gần như cùng 1 lúc với nhau. (kéo dài trong một khoảng thời gian nào đó)

Những từ trong () đặt cạnh động từ là dấu hiệu nhé