Let me restate my problem in a more clear way i think. Situation A: a accelerated rocket in flat spacetime. the observer in the rocket could think he is in a gravitation field equivalently.All experiments he do are like in a gravitation field downward. SituationB: a apple falls down under the gravitation force from the tree, or "in GR way", caused by the curved spacetime which is disturbed by the earth. Can I say that the gravity in A is different from in B? or the gravity in B is real , in the sense that it is caused by another object. After all what we called gravity is a interaction of two bodies , no matter you intepreted as curved spacetime or force, which both demand a source (the earth in B).Obviously in case A there is no such a source.