Look at these example sentences from Unit 90:
– The woman “who” lives next door is a doctor. (or The woman that lives ..)
“who” – “The woman” lives next door.
who (= the woman) is the subject.
- Where is the cheese “that” was in the refrigerator? (or the cheese which was …)
“that” – “The cheese” was in the refrigerator. that(= the cheese) is the subject
You must use who/that/which when it is the subject of the relative clause.
You cannot say “The woman lives next door is a doctor” or “Where is the cheese was in the refrigerator?”
Sometimes who/that/which is the object of the verb. For example”
– The woman “who” I wanted to see was away on vacation.
I wanted to see the “woman”
(“who” – “woman”)
who = the woman = object
I is the subject
- Have you found the key “that” you lost?
You lost “the keys”.
(“that” – “the keys”)
that = the keys = object
You is the subject
When who/that/which is the object, you can leave it out. So you can say:
– The woman I wanted to see was away. or The woman who I wanted to see …
– Have you found the keys you lost? or … the keys that you lost?
– The dress Ann bought doesn’t fit her very well. or The dress that Ann bought …
– Is there anything I can do? or … anything that I can do?
Note that we say:
– the keys you lost (not the keys you lost them)
– the dress Ann bought (not the dress Ann bought it)
Note the position of prepositions (in/to/for, etc.) in relative clauses:
Tom is talking “to” a woman – do you know her?
-> Do you know the woman (who/that) Tom is talking “to”?
I slept “in” a bed last night – it wasn’t very comfortable
-> The bed (that/which) I slept “in” last night wasn’t very comfortable.
- Are these the books you were looking for? or … the books that/which you were …
- The woman he fell in love with left him after a month. or The woman who/that he …
- The man I was sitting next to on the plane talked all the time. or The man who/that I was sitting next to …
Note that we say:
the books you were looking for (not the books you were looking for them)
You cannot use what in sentences like these (see also Unit 90C):
– Everything (that) they said was true. (not Everything what they said)
– I gave her all the money (that) I had. (not all the money what I had)
What = “the thing(s) that”:
– Did you hear what they said? (= the things that they said)