Глагол

СПРЯЖЕНИЕ ГЛАГОЛА TO BE
I am
He is
She is
It is
We are
You are
They are

СПРЯЖЕНИЕ ГЛАГОЛА TO HAVE
I have
He has
She has
It has
We have
You have
They have

ОБОРОТ THERE IS / THERE ARE
Оборот there is / there are служит для выражения наличия (отсутствия) какого-либо предмета в определенном месте или в определенное время.

PRESENT INDEFINITE
There is a picture on the wall. На стене картина.
Is there a picture on the wall? На стене есть картина?
There are pictures on the wall. На стене картины.
Are there pictures on the wall? На стене есть картины?

PAST INDEFINITE
There was a picture on the wall. На стене была картина.
Was there a picture on the wall? На стене была картина?.
There were pictures on the wall. На стене были картины.
Were there pictures on the wall? На стене были картины?

FUTURE INDEFINITE
There will be pictures on the wall. На стене будут картины.
Will there be pictures on the wall? На стене будут картины?

Выбор формы глагола to be зависит от числа существительного, следующего сразу за ним:
There is a chair and two armchairs in the room.
There are two armchairs and a chair in the room.