Why we must use "that" in the sentence "Is this the school ___ you visited"

Yes, you can use 'which' ,instead of 'that', in this sentence

An idiom has come into my mind which/that applies here: the forum mines the rich seam of relative clauses, which is good news.

Inchoate

One question: Jhumjhum wrote:"Yes, you can use 'that', instead of which, in this sentence."
I am sure this sentence is correct in terms of how it is punctuated.
On the other hand, this one is correct too:
'Yes, you can use 'that' instead of which in this sentence'.
So my question is what you think about it.
Is it also a matter of style which I should use? or emphasis o

But before I try to answer Inchoate:

THAT you visited says that this school is THE school that you visited. You are trying to show how it is different from all the other schools, the ones you did NOT visit. It restricts the optoins to the school you visited. WHICH you visited simply gives additional information about the school - you visited it, but your visit is not what is

Roger.
Thanks.

I

In this sentence " Is this the school??????????????????? you visited last year?"

First : you can either put the relative pronouns "that" or "which" because they refer to the a "thing" ="school" .

Second : you can omit the relative pronouns "Which / that" from the sentence " Is this the school??????????????????? you visited last year?" because they refer to an object not subject

Hi guys,

Why we must use "that" in the sentence "Is this the school ___that____ you visited last year?" ?

I'd like to add a small comment about the actual form of the original question. You need to use the question word-order.

ie Why must we use "that

0No, because the sentence is in Past Tense and the use of 'which' takes place when the sentence is in Present continuous tense0-

0Hi,02br
02br
00The tense does not make any difference.02br
02br
00Best wishes, Clive0-

Why use 'that' at all. It seems superfluous to me!