Conjunctions and clauses - a person who … a thing that/which … (relative clauses 1)

Question 1

WHO is for people (NOT things)

Answer 1

…A thief is a person who steals things.
…Do you know anybody who can play the piano?
…The man who phoned didn’t give his name.
…The people who work in the office are very friendly

Question 2

THAT is for things OR people

You can use that for people, but who is more usual

Answer 2

…An airplane is a machine that flies.
…Emma lives in a house that is 400 years old.
…The people that work in the office are very friendly

Question 3

WHICH is for things (NOT people):

Answer 3

…An airplane is a machine which flies. (not a machine who …)
…Emma lives in a house which is 400 years old