Open the brackets: Tom (to look) ... at the window When the teacher (to ask) ... him a quesion suddenly We (to work) ... in the garden when the rain (to begin) ... to fall.

Tom was looking at the window when the teacher asked him a question suddenly.

Том смотрел в окно, когда учитель неожиданно зада ему вопрос.

We were working in the garden when the rain began to fall.

Мы работали в саду, когда начался дождь.

В данных предложениях глаголы to look и to work употреблены в Past Continuous, а глаголы to ask и to begin - в Past Simple.