Here's why:
* Demonstrative pronouns point to something specific and their meaning depends on their location relative to the speaker.
* Examples:
* This (close to the speaker) - "This book is interesting."
* That (further away from the speaker) - "That tree is very tall."
* These (plural, close to the speaker) - "These flowers are beautiful."
* Those (plural, further away from the speaker) - "Those cars are parked in the lot."
Let me know if you'd like more information about pronouns!