Напиши предложения во множественном числе 1.it is a cat .they are cats. 2.it is a bat- 3.it is a frog- 4.it is a puppy- 5.it is a computer- 6.it is a book- 7.it is a pet- 8.it is a black dog- 9.it is a green car- 10.it is my sister-

Тут все просто.
It меняем на They.
is меняем на are т.к.are используется во мн.ч
A убирается. А к сущ.и прил.добавляем s.
They are blacks dogs. They are frogs.