This is / These are

This is a cat.

This is cat.

These are cats.

This is a book.

These are books.

These are newspapers.

This is an bird.

This is a bird.

These are birds.

These is birds.

These are an ball.

These are balls.

This is a ball.

This is ball.

This is an alligator.

This is alligator.

These are alligators.

This is a dolphin.

These are dolphin.

These are dolphins.

These are dinosaurs.

This is a dinosaur.

This is an dinosaur.

These is a sharpener.

This is an ruler.

This is a ruler.

This is an eraser.

These are lions.

These are lion.

These are tigers.

This is a lion.

This is a mango.

This is an apricot.

This is an apple.

This is a pineapple.