Are those three sentences correct? all the same? Thanks!
After a helpful and correct answer from a fellow teacher, I added:This is the room in which we stayed.
This is the room which we stayed in.
This is the room where we stayed.
And some pedants would prefer a fourth option:
This is the room that we stayed in.
The trouble for these people is that they are forced to apply one of two groundless prescriptive rules that are mutually exclusive "(that for a defining subordinate clause" and "not ending a sentence with a preposition")
PS People interested in etymology may like to imagine chains attached to each arm of the person choosing between the two 'rules'. The Greek for chains is πεδαι (pedai).
Not wanting to be one of those teachers with bees in their bonnets, which they sick onto unsuspecting students, I didn't add my further thoughts on this issue. You've guessed it – here they are.
I wrote here about phrasal verbs and what happens to them when they get used in subordinate clauses; the 'preposition' part, more commonly called the 'particle', gets moved to the end of the clause (more often than not, to the end of the sentence).
Users of Microsoft Word will have (perhaps unwittingly) crossed swords with the little Hitler that is Word's built-in 'grammar checker' – a sort of 'Strunk and White incarnate'. For example, section II.14 of that book has the title 'Use the active voice'; Word's 'grammar checker' duly objects whenever it catches the merest whiff of a passive. It wields a green underline rather as Mrs Thistlebottom† wielded a ruler in the English classroom, and helpfully suggests 'Consider rewriting' (code for 'Unless you rewrite, I'll keep nagging you as long as I have breath.')
One of the grammar checker's shibboleths is 'that in defining relative clauses' (and now the gloves are off – the underline is RED.)
<grammar_point importance="negligible" skip="yes, if you value your sanity" status="shibboleth">Now which has a full complement of inflexions: which for the subject, whose (borrowed from who) for the possessive, and the same form can be used in all sorts of object positions – by which, to which, from which ... and so on. Who is similar: who (subject) whose (possessive), whom for all kinds of object. That doesn't enjoy any of this flexibility:
Suppose I have two lawn mowers. The green one is in the shed and the red one (a 'ride-on' job), is in the garage. Woe betide you if you refer to the green one as 'the mower which is in the shed'. However, you will have Mrs Thistlebottom's blessing if you say 'The red mower, which is newer, is in the garage.'
The mower that is in the garage is redThere is the obviously/(apparently?) related word what [I am doing this,/What are you doing/Don't do that.], but it couldn't be pressed into service to bolster that.
The mower thats power source is petrol...
The mower on that you can sit while mowing...
The mower whats power source is petrol...No improvement on the that versions.
The mower on what you can sit while mowing...
Personally – though not for reasons of 'correctness' – I try to use that (or nothing) for defining subordinate clauses: 'the mower I'm sitting on' rather than 'the mower on which I'm sitting'. I am cursed by a premonition of what Word's 'grammar checker' would say; all around me I see red underlines that I have to ignore. [For some reason – just contrary, I suppose – a vision came to me just then of Lulu singing The boat which I row.] But because of the grammatical inflexibility of that I find myself from time to time having to fall back on which. I know the rule is hooey, but...
And speaking of hooey, the other thing about using that in subordinate clauses is that it forces you to 'break' another 'rule', by relegating a phrasal verb's particle to the end. (I have mentioned this before, in the red excursus in the middle of this post).
And that is the point on which I shall end.
† Mrs T is not my invention; I have mentioned her before. She haunted Dave Barry's Mister Language Person columns, which have gone the (sorely lamented) way of the songs of Tom Lehrer.
PS #WVGTbook update. I've finished OA, OE, and OI as far as the raw data is concerned. Now for the HTML bit! The scheduled 3.1 release is looking good for next month.
Update 2017.09.01.10:55 – Removed old footer