Oraciones con there is, there are , there was, there were afirmativa negativa y interrogativa?

There is : afirmativa : There is a cow.

Negativa : There isn't a cow.

Interrogativa : Is there a cow?

There are : afirmativa : There are some cows.

Negativa : There aren't some cows.

Interrogativa : Are there some cows?

There was : afirmativa : There was a cat in the livingroom.

Negativa : There wasn't a cat in the livingroom.

Interrogativa : Was there a cat in the livingroom?

There were : afirmativa : There were two cats in the livingroom.

Negativa : There weren't two cats in the livingroom.

Interrogativa : Were there two cats in the livingroom?