We use this or these with is/are to talk about things or people that are near us.
- This is my phone.
- These are my friends.
We use that or those with is/are to talk about things or people that aren’t near us.
- That's her bicycle.
- Those are her shoes.
We use this or that when we talk about singular nouns and uncountable nouns.
- This is your hat.
- This is great music.
- That's my car.
We use these or those when we talk about plural nouns.
- These are my books.
- Those are her sweets.
We can use this/that to introduce people.
- ‘Hi, Karen.’ ‘This is my friend Jack.’
- ‘Who's that?’ ‘That's Tom.’
We can use this, that, these or those in wh- questions to ask about people or things. We can reply with it or they.
- ‘What's that?’ ‘It's a present for Sue.’
- ‘What's this in English?’ ‘It's a bag.’
- ‘What are those in English?’ ‘They're pens.’
- ‘Who's that?’ ‘That's my friend, Max.’