at and in

[chum]

what's the difference?

1. I'm in the restaurant
2. I'm at the restaurant.

which is correct?

I'm good at/in English.

Thanks!

[matilda]

hi

i only heard : i'm good AT English.
but (IN) may be correct.

now about restaurant.
I think IN the restaurant means exactly in the restaurant. may be at the desk or somewhere inside it.
and AT the restaurant may mean near the restaurant