最佳答案
An erasable pen is a special kind of pen. It has some unique features. The ink used in it is specially made through special techniques. When writing with it, the ink can form a kind of erasable pigment film on the paper through the pen tip. The written words can be erased with a common eraser or a special pen within a few hours. However, after 48 hours, the words become permanent and can be preserved for a long time like those written with other pens. Moreover, the words written by the erasable pen have the advantages of not being smudged when in contact with water and not fading after long - time exposure to the sun.