Grammar reviewWho vs. that as subject relative pronouns
In each sentence here, who or that replaces the subject of the clause it introduces — not the object. That's why the pronoun sits right where the missing subject would be: “That's the neighbor who reported the noise.” → He reported the noise.
Who refers only to people. That can refer to people or things, and in everyday speech it's often the more natural, less formal choice for people too: “The girl who/that won the race.” · “The cat that lives next door.” (that/which is standard for objects and animals; some speakers use who for a pet they consider part of the family — “my dog, who loves to play fetch” — but that/which is always safe and expected here)
Why "that" is allowed here at all: this only works because these are defining relative clauses — the clause is essential to knowing which man, girl, or cat we mean. In non-defining clauses (extra, non-essential information, set off by commas), that is not allowed and only who/which can be used: “My brother, who lives in Boston, is visiting this week.” (not that)
Good to know:who, that, and which are all part of the same relative pronoun family — whom and whose cover object and possessive roles, which this exercise doesn't test.
Fill in each blank with who or that.
1. That's the man stole my purse!✓
2. That's the jacket I want to buy.✓
3. That's the girl won the race.✓
4. The students do well on the exam will be allowed to leave early.✓
5. We saw the cat lives in the house next door.✓
6. The airport is being built will be the largest in the country.✓
7. The woman sang that song is very beautiful.✓
8. People use this site will learn English very quickly.✓
9. The computer I want to buy costs $1,000.✓
10. The dinner your mother prepared was delicious.✓