Use of This
We used ‘this’ word for that thing which is near. It is singular. The word Singular describes only one.
For Examples
This is a mango.
This is a toy.
This is a bird.
Use of These
The word ‘these’ is used to point out many things which is near. It is plural. The word plural describes more than one.
For Examples
These are mangos.
These are toys.
These are birds.