To the naked eye it just looks like a square smaller than a postage stamp, but under a microscope what you see are thousands of tiny projections that are invisible to the human eye.
肉眼来看 它像是比邮票小的 一个小方片。 但是在显微镜下， 你将会看到成千上万的微小的突出物。 它们是无法被人眼看到的。