1. When the teacher came(come) into the room, two boys were playing (play) football.

Vì: Quá khứ đôi ( sự vật, sự việc này đang diễn ra thì sự vật sự việc khác cũng diễn ra song song cùng lúc) "When...,..."

Hoặc: Hành động đang diễn ra ( When the teacher came into the room ) chia quá khứ đơn , hành động xen vào ( two boys were playing football. ) chia quá khứ tiếp diễn

2. Peter turned on the TV, but nothing happened.

Vì: Vế sau chia thì quá khứ "happened" nên vế trước cũng vậy

3. When Helen walked(walk) to school, she was seeing (see) the old man again.

4. While we were running(run) in the park, Mary fell over (fall over).

Giải thích như câu 1 vì While= When

5 At 7.00 Tony got (get) out of bed, and went (go) into the bathroom.

Quá khứ đơn "At 7:00"

6 While Kate was drinking (drink) some milk, she was droped(drop) the glass.

Giải thích như câu 4

7 While I listenning (listen) to music, I were hearing(hear) the door 

Giải thích như câu 4

CHÚC EM HỌC TỐT>

`\text{1. came/ were playing}`

`\text{2. turned on/ happened}`

`\text{3. walked/ was seeing}`

`\text{4. were running/ fell over}`

`\text{5. got/ went}`

`\text{6. was drinking/ dropped}`

`\text{7. were listening/ heard }`