THIS / THAT
= are for singular nouns: one object
THIS= is for an object which is near to use: This is my lunchbox on the desk.
THAT
= is for an object which is not near to use: That is my pen in your pencil case.
THESE/THOSE
= are for plural nouns: 2 and more objects
THESE= are used for objects which are near to use: These are my new shoes.
THOSE
= are used for objects which are not near to use: Those are my classmates.
