1. We use “this” (singular) and “these” (plural) to talk about something near us.
a. This is my favorite T-shirt.
b. These are my favorite T-shirts.

2. We use “that” (singular) and “those” (plural) to talk about something far from us.
a. That is my phone.
b. Those are my phones.

3. We use “this” and “that” with singular and uncountable nouns.
a. This music makes me happy.
b. I’ll buy that book.

4. We use “these” and “those” with plural nouns.
a. These performances are amazing.
b. Have a look at these sentences.