I am going through an English grammar book written for a particular test that I am targeting. The other day, when I was studying 'Infinitives' from it, I stopped at a sentence.

To dance is fun.

I knew already that the infinitive 'To dance' worked as a subject of this sentence but there was an additional comment in the book.

'It is fun to dance' is another way of saying the same thing.

After reading it, I doubted whether the two sentences were interchangeable,and if they were not, what was the difference? but to my inconvenience, the book did not have any further information.

So, Can you explain what are the differences in terms of usage in these two? Thanks for the help.

  • 3
    They have the same meaning, but consist of two different constructions. To dance is fun is the basic version. It is fun to dance is the extraposed version with dummy "it" as subject and "to dance" as extraposed subject. The version with extraposition is more common; in fact it's the default one as far as information packaging is concerned.
    – BillJ
    Commented Aug 16, 2022 at 13:16
  • @BillJ I had thought that 'It' as a pronoun referred to the infinitive 'To dance'. But I guess, I am wrong. Could you tell me where I'm going wrong?
    – Ashutosh
    Commented Aug 16, 2022 at 14:20
  • 2
    No: it's not referntial. This is the dummy "it" that is used simply to satisfy the requirement for a subject.
    – BillJ
    Commented Aug 16, 2022 at 15:09

1 Answer 1


There's a quote by the eighteenth century poet and satirist, Alexander Pope:

To err is human; to forgive, divine

Placing the infinitives (to err, to forgive) at the start of each clause can sound (a little) archaic or formal.

If someone were to convey the sentiment above from the 1700s in contemporary spoken English (without referencing the quote) they might say something like:

It's normal to make mistakes - but it's exemplary to forgive them

We can see that in 21st century english, it's much more common to precede the infinitive with:

It is + [adjective]

But either order is correct and the meaning is identical.

Further Reading:

  • 1
    In the sentence 'It is fun to dance' Is 'fun' an adjective which describes the infinitive 'To dance'? And is 'It' a dummy subject? Asking because I have found a bit of analysis helpful in keeping things crystal-clear. I sincerely appreciate your help and guidance.
    – Ashutosh
    Commented Aug 16, 2022 at 14:29
  • 2
    @Ashutosha Yes: "fun" is an adjective. In both the basic and the extraposed versions "fun" is predicative complement of "be".
    – BillJ
    Commented Aug 16, 2022 at 17:05
  • @Roundin Your answer does not address the OP's question, which was about the contrast between an extraposition construction and its basic (non-extraposed) equivalent where a predicative adjective is present.
    – BillJ
    Commented Aug 17, 2022 at 11:25

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