This, that, these and those are sometimes tricky for English learners. They are demonstrative pronouns. We use this and that with singualr objects and these and those with plural ones.
Use this to indiacate a singular thing or person that is near you and these for plural things or people that are near you.
- This is my sister, and these people here are her friends.
Use that to indiacate a singular thing or person that is far away from you and those for plural things or people that are far away from you.
- That is my sister’s boyfriend and those people over there are his friends.