Por ejemplo:
1) to have (tener)
I have two cats.
Do you have two cats?
I don't have to cats.
When they were children they had a pink bicycle.
Did they have a pink bicycle when they were children?
When they were children they didn't have a pink bicycle.
2) to do (hacer)
What are you doing now?
I'm doing my homework now.
I'm not doing my homework now.
She has just done a cake.
Has she done a cake yet?
She hasn't done a cake yet.
3) to be (ser/estar/haber)
I was at school yesterday.
Where were you yesterday?
I wasn't at school yesterday.
Have you ever been in England?
We have never been in England.
We have been in England two times.
