Thank you for a prompt reply, Til.
So sentence 2 is problematic in terms of semantics.

How about these?
1. I have something to tell you about rugby.
2. I know a coach to tell you about rugby.

Sentence 2 sounds odd to me.
Or doesn't it?
In sentence 1 "to tell you about rugby" is not a purpose phrase, but an
adjective clause to modify "something".
Something that tells you about rugby.
In the same way can it modify "a coach", like a coach who tells you
about rugby?
I really don't think so, but I'm wondering why.

M.T.

On 15/09/22 9:35, Turner, Tildon L. wrote:
> Hi M.T.
>
> Number 2 is odd.  This lies in the use of purpose clauses.  In this case the purpose clause is "to tell you about rugby".  Therefore, 1 makes perfect sense because the speaker is stating the purpose of his or her presence.  However, 2 is ill-formed because it implies that the purpose of being a coach is to tell people about rugby.  This is a superficial explanation, but it should suffice for quick functional understanding of why 2 seems odd to you.
>
> All the best,
> Til
>
>
>
> Til Turner
> Languages and Literature
> Northern Virginia Community College
> http://blogs.nvcc.edu/tturner
> http://tilturner.wordpress.com
> www.englishiskillingme.com
> Ph: 703.323.3269
>
>
> ________________________________________
> From: Assembly for the Teaching of English Grammar [[log in to unmask]] on behalf of 高橋　美津子 [[log in to unmask]]
> Sent: Monday, September 21, 2015 8:11 PM
> To: [log in to unmask]
> Subject: I'm here to, vs I'm a coach to
>
> Hello,
> Could someone help me clear my head?
> Do both the following two sentence sound natural to you , native
> speakers of English?
> To me sentence 2 sounds a bit odd.
> I'm wondering why.
>
> 1. I'm here to tell you about rugby.
> 2. I'm a coach to tell you about rugby.
>
> M.T.
>
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