Решение:
Строим предложения в Past Simple, используя глагол 'to be'. Знак (√) означает утвердительное предложение, (X) - отрицательное, (?) - вопросительное.
- Nina was at the sports centre yesterday. (Утвердительное)
Nina wasn't at the sports centre yesterday. (Отрицательное)
Was Nina at the sports centre yesterday? (Вопросительное) - Sonya was at the post office last week. (Утвердительное)
Sonya wasn't at the post office last week. (Отрицательное)
Was Sonya at the post office last week? (Вопросительное) - Anton and Dima were in the park yesterday. (Утвердительное)
Anton and Dima weren't in the park yesterday. (Отрицательное)
Were Anton and Dima in the park yesterday? (Вопросительное) - The children were in London last year. (Утвердительное)
The children weren't in London last year. (Отрицательное)
Were the children in London last year? (Вопросительное) - Mark was at the theatre yesterday. (Утвердительное)
Mark wasn't at the theatre yesterday. (Отрицательное)
Was Mark at the theatre yesterday? (Вопросительное)