Is it "That's the family that is moving in..." or "That's (they're?) the family who is (are?) moving in..."?
I know that 'who' refers to people and 'that' refers to things. But what about when the thing IS people, such as a family? Would I say, "That's the family that is moving in next door soon.", or "That's (they're?) the family who is (are?) moving in next door soon."?
Solution 1:
You can substitute "that" for "who" in relative clauses when the clause is identifying. If the clause is non-identifying, then "that" is not permissible.