A demonstrative pronoun represents a thing or things:
- near in distance or time (this, these)
- far in distance or time (that, those)

We use this for Near and that for far as a singular. Similarly We use these for Near and those for far as a plural.
Example :
1. This tastes good.
2. Have you seen this?
3. These are bad times.
4. Do you like these?
5. That is beautiful.
6. Look at that!
7. Those were the days!