before

Yes it is used correctly.

It is asking if Prof Zig has visited here in the past or whether this is his first visit.

Thanks Nona but I have a follow-up question:

I believe, theoretically, 'Has he been here?' is sufficient to mean whether Prof Zig has visited in the past. With 'before', it reinforces the past and it clearly rules out the possibility of considering the upcoming visit although 'has been' already suggests that.

Is my interpretation correct at all?

I can see what you mean but it does sound odd to me without the 'before'. Usually 'has he been here' would refer to a very recent visit, probably on the same day. I'd think of it as 'has he been here yet?' instead of 'before'.

'Has he ever been here?' would be a suitable substitution for the original sentence as well.

Nona, I think I now understand why before is needed in the example but I have one last question about before.



According to the post above, before must go with a time reference and the same applies to ago except ago's time reference is today's date.

So Prof. Zig example clearly satisfies the befor