"THERE", "THEIR", and "THEY'RE"

"There" refers to a place. "Their" indicates possession. "They're" is a contraction for "they are." Ex.: There is a beautiful garden. Their house is nearby. They're going for a walk.

"WHO'S" and "WHOSE"

"Who's" is a contraction for "who is." "Whose" indicates possession. Ex.: Who's attending the conference? Whose jacket is this?