Why we can't say "at there"?

[Suthipong]

My student says "at There" in a sentence: I met him at there.
I told him not to use "at" before "there". But why we can't?

 

[Rover_KE]

'There' means 'at that place'.

We wouldn't say 'I met him at at that place.'

(Note: 'Why can't we say?' - not 'Why we can't say?'

Rover

 

[Suthipong]

Thank you.
I'll remember well "Why can't we say?".

 

[TheParser]

***** NOT A TEACHER *****

May I add my two cents to Rover's excellent answer?

You might remind that student that a preposition (such as "at") always needs a (pro)noun or equivalent as an object.

"There," however, is an adverb.


HAVE A NICE DAY!