它们和普通邮票是不一样的。
有纪念邮票和普通邮票。
这张圣诞贺卡是由英国格拉斯哥大学的纳米技术科学家制作的，它是如此之小，其面积仅为200x290微米，只相当于一张普通邮票的8276分之一。
It was created by nanotechnologists at the University of Glasgow. It is so small that it could fit on to the surface of a postage stamp 8,276 times.
这张圣诞贺卡是由英国格拉斯哥大学的纳米技术科学家制作的，它是如此之小，其面积仅为200x290微米，只相当于一张普通邮票的8276分之一。
It was created by nanotechnologists at the University of Glasgow. It is so small that it could fit on to the surface of a postage stamp 8,276 times.
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