There are some words in the English language that are pronounced the same, but are spelled differently and have different meanings (these words are called homophones). One of the more confusing examples is knowing how and when to correctly use the words there, their, and they’re.
There refers to a place, either concrete (“over there by the door”) or abstract (“it's nice there”).
Ex.: “The keys are over there by the door.”
Ex.: “Just set them down over there.”
Combined with the verb be (such as is, are, was, were), there can also refer to the existence of something; similarly, it can be used to introduce something for the first time.
Ex.: “There is a new store in town.”
Ex.: “In a hole in the ground there lived a Hobbit.”
If you're still unsure, you can test this by replacing there with here; if the sentence still makes sense, then you have used the word correctly.
Their is a possessive adjective which indicates that a particular noun belongs to them.
Ex.: They left their books on the table. (The books belonging to them.)
If you’re still unsure, you can test this by replacing their with our; if the sentence still makes sense, then you have used the word correctly.
They’re is a contraction of they and are. It is used only as a subject (who or what is performing the action) or verb (the action itself), and never as a modifier.
Ex.: “They’re going to the movies tonight.”
Ex.: “I’m glad they’re still serving breakfast this late in the day.”
If you’re still unsure, you can test this by replacing they’re with they are; if the sentence still makes sense, then you have used the word correctly.
Some Examples of Using There, Their, and They’re Incorrectly
“Their are a lot of people here.”
“They’re food was starting to get cold.”
“The children sat at the table to do there homework.”