chia theo Thì quá khứ tiếp diễn fly = cry = see = Chia thì quá khứ đơn hoặc quá khứ tiếp diễn thích hợp 1.The aeroplane (catch)....... fire just when it (take)........... off 2.The lights (go).... out when we(discuss)......the plans for the following morning 3.Proesor Ward (give)...... the lecture when the students' riots (begin)  

was/ were flying

was/were crying

was/were seeing

caught-was taking

went-were discussing

was giving-began