Which in English: translation and usage rules

In English, which is used to express a choice or to connect two ideas in a sentence. Understanding its different roles, interrogative and relative, helps you avoid confusion, especially when deciding when to use which vs that in your writing.

What are the main uses of which?

Which serves different grammatical functions depending on the context. Here are its primary uses:

Context	Grammatical Function	Example
Choice among items	Interrogative adjective/pronoun	Which colour do you prefer?
Relative pronoun (things)	Non-restrictive clause	The bag, which is on the table, is mine.
Referring to a previous clause	Sentence relative	He arrived late, which surprised everyone.
Plural choice	Interrogative pronoun	Which of these books are yours?

Which as an interrogative adjective or pronoun

In its interrogative role, which asks for a choice between several predefined options. When used as an interrogative adjective, it is followed directly by a noun:

English Example	Meaning
Which house do you want, the blue or the red one?	Asking for a specific choice between two houses.
Which bag would you rather I wear with this dress?	Selecting from a known collection of bags.
Which flavour do you prefer?	Choosing from available flavors.
Which train should we take?	Deciding on a specific scheduled train.
Which country would you like to visit first?	Picking from a mental list of destinations.

When used as an interrogative pronoun, it directly replaces a known noun:

English Example	Meaning
Which of the two cars is yours?	Identifying ownership between two options.
Which of these hats will you take?	Selecting a hat from a specific group.
Which of you is responsible?	Singling out a person from a group.
Which of these options suits you best?	Choosing the best available alternative.

How to answer a question starting with which

Several structures are possible when answering a question introduced by which.

Situation	Answer	Explanation
Pointing to a specific item	This one / That one	Used when indicating a nearby or distant object.
Specifying a characteristic	The one with the red band	Used to describe the chosen item.
Having no preference	Any / Any one	Used when all options are equally acceptable.
Accepting everything	All of them	Used to select the entire group.
Rejecting all options	None of them	Used when no option is suitable.
Answering precisely	The blue one / The first one	Used to give a direct, specific choice.

Complete examples:

Question	Answer	Context
Which of these hats will you take, John?	I’ll take this one / the one with the red band.	Making a specific selection.
Which flavour do you prefer, blackberry or melon?	Any of them.	Showing no specific preference.
Which dress should I wear tonight?	The black one.	Giving a direct recommendation.

Which as a relative pronoun and the that vs which rule

As a relative pronoun, which connects two parts of a sentence. It always refers to a thing, never a person (for people, we use who). This is where many students wonder when to use which vs that. Case 1: Non-restrictive clauses. In American English, which is used for non-restrictive clauses (adding extra info), separated by commas. British English allows which for restrictive clauses too:

English Example	Clause Type	Antecedent of which
I own a flat, which is just a few minutes walk away.	Non-restrictive (adds extra info)	The flat
The basket, which I carry on my head, contains strawberries.	Non-restrictive	The basket
The package, which is in the cupboard, does not belong to me.	Non-restrictive	The package
I have a dress which is identical to yours.	Restrictive (common in UK English)	The dress

Case 2: which summarizing the entire preceding clause:

English Example	Meaning
He said he was ill, which was not true.	The fact that he said he was ill was a lie.
The store was closed when we arrived, which was to be expected.	The closure of the store was expected.
She passed the exam, which made her parents very proud.	Her success made her parents proud.
The park will be closed until next week, which I am not happy about.	The closure is the reason for my unhappiness.
They came late, which I feared.	Their late arrival was what I was afraid of.
He lost his keys again, which is becoming a habit.	The repeated loss of keys is the habit.

Which vs what: how to tell the difference?

This is a very common confusion. The rule is simple: which implies a limited and defined number of options. What asks an open question without predefined choices.

Context	Which	What
Options defined in advance	Which colour do you want: blue or red?	N/A
Open question, no constraints	N/A	What colour do you like?
Choice from a known list	Which film shall we watch tonight? (from available ones)	N/A
General, unlimited preference	N/A	What kind of film do you like?
Referring to the previous clause	He lied, which surprised me.	What surprised me was his reaction. (subject)

Tip: if the possible choices are mentioned or implicitly known in the conversation, which is correct. If the question is entirely open, what is required.

Common expressions and phrases with which

Expression	Meaning	Usage
Which one?	Asking to specify	Common spoken request for clarification
Which way?	Asking for direction	Used for navigation
Which means that…	Implying a consequence	Very common logical connector
…of which…	Indicating possession or inclusion	Formal or written register
…in which case…	Presenting a hypothetical scenario	Formal register
…at which point…	Indicating a specific moment	Chronological narrative or explanation
Which is why…	Explaining a reason	Explaining a consequence
Which brings us to…	Transitioning to a new topic	Transition in a speech or presentation

Practice Exercise

Test your knowledge on the use of which in English: