`1.` It was raining heavily when I went to school

`2.` While I was writing many letters, the phone rang

`3.` I was having breakfast when she came

`4.` My aunt was living in France while I was living in Viet Nam

`5.` When Robert was talking with his wife, I met him

`6.` While Mary was finishing her homework, her mother was cooking for dinner

`7.` I was walking home last night when it rained

`8.` While the baby was sleeping, I came home

`9.` When I was studied English, they were playing piano

`10.` The children was playing in the garden when their mother went out

`-` Hành động đang xảy ra trong quá khứ `→` QKTD

`-` Hành động chen vào `→` QKĐ

`-` Hai hành động cùng đồng thời xảy ra `->` Cả 2 mệnh đề QKTD

*Cấu trúc thì quá khứ tiếp diễn:

`(+)` S + was/ were + V_ing

`(- )` S + was/ were + not + V_ing

`(? )` Was/ Were + S + V_ing?

*Cấu trúc thì quá khứ đơn:

`(+)` S + V_ed/ V2

`(- )` S + didn't+ V_inf

`(? )` Did + S + V_inf?