this one is pretty tough for me... Emotion: sad is there a difference for those prepositions in this context?

She is at the beach
She is on the beach
She is in the beach
In most circumstances you could say either "on the beach" or "at the beach." "At the beach" is a little more general -- if you say "she is at the beach," she might be in the water, or at a shop near the beach buying ice cream, or even on vacation in a beach town. If you way "she is on the beach," it means she is actually sitting, walking or lying on the sand. We don't say "in the beach."
I got it, Khoff!
thanks a lot!