暑假在家,正闲得无聊,我忽然看见妈妈摆在门口的一双双皮鞋都戴上了“灰色面具”。我灵机一动,何不给它们“洗洗脸”呢?说干就干。我先拿干净的抹布把鞋子上的灰擦拭干净,接着给皮鞋均匀地涂上鞋油,随后用抹布使劲儿擦,皮鞋终于露出了光彩。可我又不禁疑惑,为什么用鞋油擦过之后,旧皮鞋就变亮了呢? Summer vacation at home, is bored, I suddenly saw my mother put a pair of shoes in the door wearing “gray mask.” I am inspired, why not give them “wash your face”? I first take a clean rag to wipe the ash on the shoes clean, then evenly coated shoe polish, then wipe with a rag, shoes finally revealed a glitter. But I can not help but wonder why the old shoes became brighter after they were rubbed with the shoe polish.