So, I happened to be reading a grammar book in which I came across this weird looking sentence.

This is the car of which parts are not available now.

I think it should have been something like this:

This is the car, parts of which are not available now.

If the improvised version is correct, I do not know why. Can you guys help me with such constructions?

  • 1
    Can you tell us the name of the book and the context in which you found this sentence?
    – Shoe
    Nov 15, 2023 at 8:10
  • Assuming you're only interested in the position of "of which", see e.g. this question: both are correct, although "parts of which" (or "whose parts") is more common and to me "of which parts" sounds too formal for what's presumably a car manual or something similar. There are many similar questions if you search for of which.
    – Stuart F
    Nov 15, 2023 at 9:46
  • 6
    With reference to a car, parts has the particular meaning 'replacement parts of the engine', while parts of which sounds more general. I think it would have been better expressed as the car for which parts are not available. Nov 15, 2023 at 10:09
  • 2
    In support of @KateBunting it's far more likely to be "for" than "of." If someone says that sentence to you, and you don't know why, a correct response would be to ask "why do you need parts of that car?" If your interlocutor says "I don't need parts of the car; I need parts for the car," then the first sentence should have used "for which" rather than "of which." Aside: the punctuation of your second sentence is incorrect; there should be no comma. The more colloquial rendering is "this is the car that you can't get parts for now" (a construction long frowned upon by prescriptivists).
    – phoog
    Nov 15, 2023 at 12:21
  • 2
    @L Lawliet What grammar book is that? I would suggest "This is the car whose parts are not available now.
    – BillJ
    Nov 15, 2023 at 15:44

2 Answers 2


Your version is correct; the grammar book’s is not.

This is from The Chicago Manual of Style:

5: Grammar and Usage
5.64: “Whose” and “of which”
The relatives who and which can both take whose as a possessive form (whose substitutes for of which) {a movie the conclusion of which is unforgettable} {a movie whose conclusion is unforgettable}.
Source: The Chicago Manual of Style

You can compare these to see how the possessive relative construction works:

This is a movie the conclusion [of which] is unforgettable. —>

This is a movie the conclusion [of this movie] is unforgettable. —>

This is a movie [whose] conclusion is unforgettable.

This is the car, parts [of which] are not available now. —>

This is the car, parts [of this car] are not available now. —>

This is the car [whose] parts are not available now.

Here’s what’s wrong with the book’s version:

*This is the car [of which] parts are not available now. —>

*This is the car [of this car] parts are not available now. —>

PS: The CMOS entry continues:

Some writers object to using whose as a replacement for of which, especially when the subject is not human, but the usage is centuries old and is widely accepted as preventing unnecessary awkwardness. Compare the company whose stock rose faster with the company the stock of which rose faster. Either form is acceptable, but the possessive whose is far smoother.

PPS: In your example, even if parts of which... is an essential clause, it nonetheless needs a “comma of clarity” between car and parts to prevent a read of car parts.


There is a very subtle difference between the two in some regions, like my region in the Southern United States.

This is the car, parts of which are not available now.

Would imply that the parts are the parts of the car, such that the car was disassembled, the parts were moved, and a few of the parts were lost.

This is the char, of which parts are not available now.

Implies that the parts are "of the car" meaning they are representatives of parts that car might have, but aren't directly the parts the car had. In other words, it implies that one has a whole car, but replacement parts are not available now.

There is very little that indicates this is a common way of reading these two sentences beyond my local region; but, it does explain why some areas still use "of which" when other areas see it only as a way of speaking more formally.

  • Please cite sources for this claim about a potential difference in meaning, in your region/dialect or anywhere else. I doubt that most others, even in your area, perceive a similar difference.
    – alphabet
    Nov 15, 2023 at 18:12
  • Then come on over and ask my neighbors :) Sorry for the joke, but it is not possibly to authoritatively prove what another thinks, unless you're that other person. I'm just reporting how people react when we use one phrase as opposed to the other.
    – Edwin Buck
    Nov 15, 2023 at 23:31
  • You may well be right, but you need to cite sources for that, other than just your intuitions about how you think people react.
    – alphabet
    Nov 16, 2023 at 0:02

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