+0
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
+2
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."
Comments  
I got it, Khoff!
thanks a lot!