Demonstrative Pronouns This · that · these · those
Used to explain what we are talking about. We sometimes use them with nouns and we sometimes use them on their own

Singular:
This ◦ That

Plural:
These ◦ Those

this and these to talk about things close to us.
that and those to talk about things at some distance away from us.

What about this shirt for Oliver?
No, hold on, what about that one over there?

this ↔ here • that ↔ there

This market is amazing.
➲ here. I'm in the market

That market looks amazing.
➲ there. I'm not in the market

What about time? How does time affect this or that?
We use that to show distance in time as well as distance in space.

This is a good film.
➲ we're watching it now.

That was a good film.
➲ we saw it at some time in the past.

Are this·these and that·those always used with nouns?
No, we can use them as pronouns, without nouns, when it's obvious what they refer to.

What do you think about these for your Uncle Bob?
➲ pointing to trousers

I've never seen Uncle Bob in trousers like those.
➲ those trousers, but we don't need to repeat trousers.

Who was that?

What about phone language? How do people use this and that?

When you explain who is talking you say, 'Hi, this is Dan.'
And to check who is speaking, you can say, 'Is that Jenny?'

What about introducing people to each other? Do I use this or that?

When you're introducing one person to another person, you say,
'Juliette, this is Marc'.

this and that can refer to what somebody has said or what has happened. This could be several things or ideas.

That's right.
➲ everything you said

This is work you know!
➲ all the things I'm doing

That was a great concert!
➲ something that has just happened