Make these sentences negative. His sister works in tayford. Their parents

1. His sister works in Tayford.
His sister doesnt work in Tayford.
Does his sister work in Tayford?
2. Their parents live in London.
Their parents dont live in London.
Do their parents live in London?
3. Theyve got a big house.
They havent got a big house.
Have they got a big house?
4. They went to Oxford last year.
They didnt go to Oxford last year.
Did they go to Oxford last year?
5. Colins grandparents were doctors.
Colins grandparents werent doctors.
Were Colins grandparents doctors?