this : местоимение
This is my favorite T-shirt.
Anything would be better than this.
“What's this right here?” “It's a very rare gold coin.”
Would you take a look at this, please?
All of this is mine.
This is the most fun I've had in years!
“It will be difficult.” “This is true.”
What is the meaning of this?
This is silver and that is gold.
This is my jacket and that's yours.
it : pronoun, nominative it, possessive its or it, objective it; plural nominative they, possessive their or theirs, objective them.
that : что что, чтобы