Put the verbs in brackets into the past simple or past continuous. 1 When the teacher __________ (come) into the room, two boys __________ (play) football. 2 Peter __________ (turn on) the TV, but nothing __________ (see). 3 When Helen __________ (walk) to school, she __________ (see) her friend again. 4 While we __________ (run) in the park, Mary __________ (fall).

1 When the teacher came into the room, two boys were playing football.
2 Peter turned on the TV, but nothing appeared.
3 When Helen was walking to school, she saw her friend again.
4 While we were running in the park, Mary fell.

Объяснение:
В этих предложениях нужно использовать либо Past Simple, либо Past Continuous, в зависимости от контекста. Past Simple используется для коротких, завершенных действий, а Past Continuous - для действий, которые происходили в течение какого-то времени или прервались другим действием.