According to Practical English Usage, 4th ed., Michael Swan (2017), section 'preparatory it', preparatory it is not used with complements. He gives these two examples (section 7 in the screenshot):


CORRECT: This chair is comfortable to sit on.

WRONG: It is comfortable to sit on this chair.

NOTE: 'to sit on' is the complement of 'comfortable'.


CORRECT: The impression was given that travel expenses would be paid.

WRONG: It was given the impression that travel expenses would be paid.

NOTE: 'that travel expenses' is the complement of the 'impression'.

I believe I understand where he aims at, but I tend to believe that I, from time to time/or even often, hear such constructs (but I'm not 100% sure that it really is the same complement construct), that Swan says is not correct. Here are some examples:

Example 1
It is difficult to drive this car.
(This car is difficult to drive.)

Example 2
It is easy to ride on that mare.
(That mare is easy to ride on.)

Example 3
It is fascinating to watch this film.
(This film is fascinating to watch.)

I'm not too sure whether my examples are well chosen, but to me they seem to represent the exact same logic/problem.

  1. Do people not use such constructs?

  2. Are they considered ungrammatical by linguists but accepted in everyday speech/writing?

NOTE: Yes, I'm aware that there is one other question here in the forum. However, it does not address possible examples that we might hear every now and then.

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  • 2
    Comfortable is an interesting case. The comfort goes to the occupant, but the property is imputed to the chair. Note the -able suffix; comfortable is a modal, and behaves erratically, as all modals do. I also wouldn't agree with the ungrammatical label for the extraposed version -- it's not as common but it's OK. Mar 5 at 16:24
  • 2
    @YosefBaskin - This is the original sentence from the book. I think it depends on the chair. We sit on kitchen chairs but we sit in armchairs.
    – JoHKa
    Mar 5 at 16:33
  • 2
    Strictly, whether I sit 'in' or 'on' a chair depends on the type of chair. An ordinary dining or office chair I sit 'on', not 'in'; an arm chair I sit 'in'.
    – Tuffy
    Mar 5 at 19:49
  • 1
    @rhetorician It is perfectly natural in English; you might as well disapprove of wildflowers. The fact that, on the other hand, is dangerous. It's one way to get a noun phrase where you need one, which is handy, but fact commits the speaker to the truth of the following proposition ("It's a fact that ..."), and you don't wanna do that unless you can vouch for it personally. You might get blamed for passing on fake news, or something. Mar 6 at 17:01
  • 2
    Maybe, Swan thinks we should only be allowed to say It's comforting to sit there. If so, imho that makes him just a prescriptive pedant. (And there was me thinking he was of the descriptive persuasion! :) Mar 8 at 2:27

3 Answers 3


It is comfortable to sit on this chair.

This is a very bad example, since on the obvious reading it is perfectly correct.

Here is what I suspect he may be trying to say, without having read the book. There are two ways you could try to read this sentence:

  1. It is [comfortable to sit on] this chair.
  2. It is comfortable [to sit on this chair.]

In (1), the extraposed subject is "this chair," and "to sit on" is a complement of "comfortable." In (2), the extraposed subject is "to sit on this chair," and "on this chair" is a complement of "to sit."

I suspect that the author's point is that reading (1) is invalid, i.e. that nobody could read the sentence and interpret it that way. In other words, his point is that, if you start with:

[To sit on this chair] is [comfortable.]

You can extrapose the subject and replace it with "it":

It is [comfortable] [to sit on this chair.]

But if you start with:

[This chair] is [comfortable to sit on.]

You can't perform extraposition while keeping "this chair" as the subject:

*It is [comfortable to sit on] [this chair.]

  • Thank you for you fantastic reply. And yes, 'to sit on' is the complement of 'comfortable' as far as Swan is concerned. I have added this info in my post and also put in the 2nd example that Swan gives in his book. These are the 'only two' examples he provides the reader with.
    – JoHKa
    Mar 6 at 17:51
  • I don't have access to the 4th Edition, but 3rd Edition doesn't have any examples like the comfortable chair cited by OP. But what it does say, on P446, is Preparatory it is common before be + adjective/noun. With example It's nice to talk to you, which as he points out, is more natural than To talk to you is nice. That looks the same as the comfy chair to me! Mar 7 at 19:09
  • @FumbleFingers - I have added a screenshot of the page. It is from the PEU (4th ed.) Android app.
    – JoHKa
    Mar 8 at 9:29
  • Yes, I found it for myself after posting that comment. I still think the comfy chair is a bad example. Like I said, his other example It was given the impression that travel expenses would be paid is equally unacceptable to me, but I don't object to the comfy chair example at all. Mar 8 at 11:20

I for one see a problem with (1):

(1) It is comfortable to sit on this chair.

As @alphabet has noted, the only plausible way to parse (1) would be to treat to sit on this chair as an extraposed subject that is related to the dummy it.

If (1) is to work, therefore, (1') should also work:

(1') To sit on this chair is comfortable.

Both (1) and (1') are understandable, but not all sentences that are understandable are also natural or even grammatical.

The problem I see with (1) and (1') is that, in order for these to work, the adjective comfortable has to describe how the action of sitting on this chair causes someone to feel. But the adjective is normally used to describe how an object such as a chair makes someone feel or how someone feels in a particular situation (e.g., when sitting on a chair). So it's not entirely clear whether (1) are (1') are natural or even grammatical.

Unlike comfortable, such adjectives as difficult, easy, fascinating can normally be used to describe an action, so I have no problem with OP's examples 1-3.


WRONG: It is comfortable to sit on this chair.

WRONG: It was given the impression that travel expenses would be paid.

The point that Quirk is trying to make is the difference between a dummy it and a real it.

The examples above are wrong because the "it" is not a dummy it (which has only a vague referent) but is a real "it" as they are replaceable by he or she.

In the case of a dummy it - the "it" cannot be replaced by he/she (or other appropriate pronoun).

"It is well-known that the earth is flat."

*"He is well-known that the earth is flat."

Real it:

"It was seen on the horizon."

"He was seen on the horizon."

I think that this is a genuinely badly thought-out example:

*It is comfortable to sit on this chair.

*He is comfortable (in comfort) to sit on this chair.

*The dog is comfortable (in comfort) to sit on this chair.

(I don't think that this is a good example as "comfortable" can have the meaning of "not disquieted" in which case both are correct.)


*It was given the impression that travel expenses would be paid.

He was given the impression that travel expenses would be paid.

Where we see that "It" is an inappropriate dummy "it" as the substitution cannot be made.

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