Это глагол to be.Он используeтся тогда когда в прeдложeнии нeт дeйствия. Для каждого лица он свой: I am
We, you are и т.д.
He is reading a book now.
She is doing her homework.
My mother is sitting///
I am still writing a letter.
They are playing football.
It is snowing now.
We are having dinner now.
It is still raining.
Why are you talking?
The girl is drawing a picture...
My friend helps me to do my homework
In the library we choose books to read
On saturdays she looks foreign magazines
We go to the institute on weekdays
Every weei i spend a latter to parents
He always tells interesting stories to children
Пятое Dinosaur остальное не понятно, там может какие нибудь примечания есть?