Like many other words in English Grammar, ‘Which’ and ‘That’ also confuse many learners. It is simply because both these words play almost the same role in introducing additional clauses in a sentence. However, their opting for either of these grammatical words can change the meaning of the sentence. As far ‘Which’ is concerned, it is used in the non-restrictive clause to give more details about the thing talked about in the sentence. On the other hand, ‘That’ is used to introduce a restrictive clause to limit the details. Consider these two sentences: ‘The book that has a red cover is mine’ and ‘The book, which has a red cover, is mine’. The first sentence suggests that the speaker is telling that he has only one book with red color; in the second sentence, however, he is indicating to a particular out of many. A notable difference can be seen in the usage of both these words as Comma is used before ‘Which’, while ‘That’ does not need any punctuation mark. Another thing worth mentioning is that the Determiner ‘Which’ can also form an Interrogative sentence when it starts a sentence e.g. ‘Which way leads to the market’? or ‘Which country has the biggest desert?’ On the other hand, the determiner ‘That’ cannot be used to form an Interrogative sentence and can only be used either as a relative Pronoun, Adjective, Conjunction to introduce a Subordinate Restrictive clause or as a Demonstrative Pronoun at the start of a sentence.
Being the one singled out, implied, or understood
What particular one or ones of a number of things or people
Which part of town do you mean?.
Being the one further removed or less obvious
That route is shorter than this one.
Any one or any number of; whichever
Use which door you please.
To such an extent or degree
Is your problem that complicated?.
Being the one or ones previously mentioned or implied
It started to rain, at which point we ran.
To a high degree; very
Didn't take what he said that seriously.
(interrogative) What, of those mentioned or implied.
Which song shall we play?
They couldn't decide which song to play.
Which one is bigger?
Show me which one is bigger.
Used to introduce a noun clause that is usually the subject or object of a verb or a predicate nominative
"That contemporary American English is exuberantly vigorous is undeniable" (William Arrowsmith).
The/Any ... that; whichever.
You may go which way you please.
Used to introduce a subordinate clause stating a result, wish, purpose, reason, or cause
She hoped that he would arrive on time. He was saddened that she felt so little for him.
Designates the one(s) previously mentioned.
He once owned a painting of the house, which painting would later be stolen.
Yesterday, I met three men with long beards, which men I remember vividly.
For several seconds he sat in silence, during which time the tea and sandwiches arrived.
I'm thinking of getting a new car, in which case I'd get a red one.
Used to introduce an anticipated subordinate clause following the expletive it occurring as subject of the verb
It is true that dental work is expensive.
(interrogative) What one or ones (of those mentioned or implied).
Which is which?
By now, you must surely know which is which.
Which is bigger, the red one or the blue one?
I'm unable to determine which is bigger.
Which of these do you want to keep?
Used to introduce a subordinate clause modifying an adverb or adverbial expression
Will go anywhere that they are welcome.
The/Any ones that; whichever.
Please take which you please.
Used to introduce a subordinate clause that is joined to an adjective or noun as a complement
Was sure that she was right.
Persists in the belief that rates will rise soon.
(relative) Introduces a relative clause giving further information about something previously mentioned.
He walked by a door with a sign, which read: PRIVATE OFFICE.
I found my camera, which I thought I'd lost, under the bed.
No art can be properly understood apart from the culture of which it is a part.
He had to leave, which was very difficult.
Used to introduce an elliptical exclamation of desire
Oh, that I were rich!.
Used of people (now generally whom, that; which remains possible with words also referred to by it like baby, child).}}
Introducing a clause which is the subject or object of a verb (such as one involving reported speech), or which is a complement to a previous statement.
He told me that the book is a good read.
I believe that it is true. — She is convinced that he is British.
That she will come is almost certain.
Of what sort or kind; what; what a; who.
And which they weren and of what degree.
Introducing a subordinate clause expressing a reason or cause: because, in that.
Be glad that you have enough to eat.
A relative pronoun, used esp. in referring to an antecedent noun or clause, but sometimes with reference to what is specified or implied in a sentence, or to a following noun or clause (generally involving a reference, however, to something which has preceded). It is used in all numbers and genders, and was formerly used of persons.
And when thou fail'st - as God forbid the hour! -Must Edward fall, which peril heaven forfend!
God . . . rested on the seventh day from all his work which he had made.
Our Father, which art in heaven.
The temple of God is holy, which temple ye are.
(dated) Introducing a subordinate clause that expresses an aim, purpose, or goal ("final"), and usually contains the auxiliaries may, might, or should: so, so that.
A compound relative or indefinite pronoun, standing for any one which, whichever, that which, those which, the . . . which, and the like; as, take which you will.
Do not they blaspheme that worthy name by the which ye are called?
Introducing — especially, but not exclusively, with an antecedent like so or such — a subordinate clause expressing a result, consequence, or effect.
The noise was so loud that she woke up.
The problem was sufficiently important that it had to be addressed.
Introducing a premise or supposition for consideration: seeing as; inasmuch as; given that; as would appear from the fact that.
Introducing a subordinate clause modifying an adverb.
Was John there? — Not that I saw.
How often did she visit him? — Twice that I saw.
Introducing an exclamation expressing a desire or wish.
Oh that spring would come!
Introducing an exclamation expressing a strong emotion such as sadness or surprise.
The (thing, person, idea, etc) indicated or understood from context, especially if more remote physically, temporally or mentally than one designated as "this", or if expressing distinction.
That book is a good read. This one isn't.
That battle was in 1450.
That cat of yours is evil.
(demonstrative) The thing, person, idea, quality, event, action, or time indicated or understood from context, especially if more remote geographically, temporally or mentally than one designated as "this", or if expressing distinction.
That's my car over there.
He went home, and after that I never saw him again.
The known (thing); used to refer to something just said.
They're getting divorced. What do you think about that?
(demonstrative) The aforementioned quality or proposition; used to emphatically affirm or deny a previous statement or question.
The water is so cold! — That it is.
Would you like another piece of cake? — That I would!
We think that you stole the tarts. — That I did not!
(relative) (plural that) Which, who; representing a subject, direct object, indirect object, or object of a preposition.
The CPR course that she took really came in handy.
The house that he lived in was old and dilapidated.
(colloquial) Used in place of relative adverbs such as where or when; often omitted.
The place that [= where or to which] I went last year
The last time that [= when] I went to Europe
Clipping of that is; used to reinforce the preceding assertion or statement.
That's proper funny, that.
(degree) To a given extent or degree.
"The ribbon was that thin." "I disagree, I say it was not that thin, it was thicker... or maybe thinner..."
(degree) To a great extent or degree; very, particularly in negative constructions.
I'm just not that sick.
I did the run last year, and it wasn't that difficult.
To such an extent; so. in positive constructions.
Ooh, I was that happy I nearly kissed her.
(philosophy) Something being indicated that is there; one of those.
As a demonstrative pronoun (pl. Those), that usually points out, or refers to, a person or thing previously mentioned, or supposed to be understood. That, as a demonstrative, may precede the noun to which it refers; as, that which he has said is true; those in the basket are good apples.
The early fame of Gratian was equal to that of the most celebrated princes.
That be far from thee, to do after this manner, to slay the righteous with the wicked.
And when Moses heard that, he was content.
I will know your business, Harry, that I will.
Two principles in human nature reign;Self-love, to urge, and Reason, to restrain;Nor this a good, nor that a bad we call.
If the Lord will, we shall live, and do this or that.
As an adjective, that has the same demonstrative force as the pronoun, but is followed by a noun.
It shall be more tolerable for Sodom and Gomorrah in the day of judgment, than for that city.
The woman was made whole from that hour.
Upon a day out riden knightes two . . . That one of them came home, that other not.
As a relative pronoun, that is equivalent to who or which, serving to point out, and make definite, a person or thing spoken of, or alluded to, before, and may be either singular or plural.
He that reproveth a scorner getteth to himself shame.
A judgment that is equal and impartial must incline to the greater probabilities.
We speak that we do know, and testify that we have seen.
That I have done it is thyself to wite [blame].
The ship that somebody was sailing in.
I saw to-day a corpse yborn to churchThat now on Monday last I saw him wirche [work].
That that dieth, let it die; and that that is to cut off, let it be cut off.
As a conjunction, that retains much of its force as a demonstrative pronoun.
To introduce a clause employed as the object of the preceding verb, or as the subject or predicate nominative of a verb.
She tells them 't is a causeless fantasy,And childish error, that they are afraid.
I have shewed before, that a mere possibility to the contrary, can by no means hinder a thing from being highly credible.
As adverb: To such a degree; so; as, he was that frightened he could say nothing.
With singing, laughing, ogling, and all that.
The rank is but the guinea's stamp,The man's the gowd [gold] for a'that.
To introduce, a reason or cause; - equivalent to for that, in that, for the reason that, because.
He does hear me;And that he does, I weep.
To introduce a purpose; - usually followed by may, or might, and frequently preceded by so, in order, to the end, etc.
These things I say, that ye might be saved.
To the end that he may prolong his days.
To introduce a consequence, result, or effect; - usually preceded by so or such, sometimes by that.
The birds their notes renew, and bleating herdsAttest their joy, that hill and valley rings.
He gazed so longThat both his eyes were dazzled.
So wept Duessa until eventide,That shining lamps in Jove's high course were lit.
Is not this the dayThat Hermia should give answer of her choice?
In an elliptical sentence to introduce a dependent sentence expressing a wish, or a cause of surprise, indignation, or the like.
Ha, cousin Silence, that thou hadst seen that that this knight and I have seen!
O God, that right should thus overcome might!
To try if that our own be ours or no.
When he had carried Rome and that we lookedFor no less spoil than glory.
‘That’, basically, has multiple statuses in English Grammar just like many other words. It is mostly termed as ‘Determiner’ as it determines or identifies the thing being talked about in a sentence. It is also given the title of as ‘Subordinator’ since it links the Subordinate Clause with the main clause. Besides, ‘That’ is also used as Adjective, Adverb, as well as Relative Pronoun to indicate or relate a particular person or thing. ‘That’ is mostly used with restrictive clauses to limit the meaning of the thing being talked in the sentence e.g. ‘I like to read the book that has changed my life’. And as a Demonstrative Pronoun, ‘That’ indicate a thing or person e.g. ‘I’d like to buy that shirt’, meaning the shirt lying a bit far from the speaker.
‘Which’ is also having more than one title in English Grammar. Besides being a Determiner, just like ‘That’, it also relates Person or Thing and plays the role of an Adjective as well. ‘Which’ is mostly used in non-restrictive clauses where it needs a Comma to get support from. Though ‘Which’ has almost the same titles as ‘That’ does, it can also be used at the start of a sentence to make it Interrogative e.g. ‘Which cinema do you like to watch a movie in’? or ‘Which film star has won the Oscar this year’?