He has a student two ears ago,they were in the park last saturday в отрицательную и вопросительную форму

They were in the park last Saturday.
They were not in the park last Saturday.
Were they in the park last Saturday?

He was a student two years ago. 
He wasn't a student two years ago.
Was he a student two years ago?
Я предполагаю так. Если предложение не такое, напишите, я исправлю