Negative sentence This These That Those

ประโยคปฏิเสธ การพูดว่า นี้-เหล่านี้, นั้น-เหล่านั้น

This is not a helmet.

This is not a necklace.
This is not a radio.
This is not a computer.
This is not a phone.
That's not a bird.
That's not a bear.
That's not a dog.
These aren't ants.
These aren't oranges.
These aren't mangoes.
Those aren't bananas.
Those aren't roses.
Those aren't apples.
It's not a duck.
It's not a toy.
It's not a robot.