Задай вопросы к выделенным словам . my cat saw a grey mouse - we played in the garden - we watched a star yesterday - they were at home , because it was cold -

1. My cat saw a mouse, didn't it?
2.Where did we play?
3.When did we whatch the star?
4. Why were they at home? или Why did they were at home?

В 4 вроде второе правильное. просто не помню