“…We refer to the excellent monographs [32,33,34,42] for a panorama of the field. In recent years, many works in probability and stochastic processes illustrate the diffusion universality in various models: a well-understood model is the random conductance model, see [14] for a survey, and especially the heat kernel bound and invariance principle is established for the percolation clusters in [13,37,41,36,11,12,40]; from the view point of stochastic homogenization, the quantitative results are also proved in a series of work [9,6,10,7,26,27,23,24,25], and the monograph [8], and these techiques also apply on the percolation clusters setting, as shown in [5,19,28,20]; for the system of hard-spheres, Bodineau, Gallagher and Saint-Raymond prove that Brownian motion is the Boltzmann-Grad limit of a tagged particle in [16,15,17]. All these works make us believe that the model in this work should also have diffusive behavior in large scale or long time.…”