I am something that has teeth but can't eat. What am I?

I am something that always increases when I share myself with others. What am I? am i messing something I am something that can run but never walk what am I? 猜猜：I am something that can run but can not walk .What am I? I am something that has teeth but can't eat. What am I? I am something that makes everything visible,but myself is unseen.What am I am something that can run but cannot walk.What am I am something that can run but never walk what am I am something that is lighter than a feather ,and yet harder to hold.Whai am Something that I never I am 20 something是什么意思? I'am going do something I am something that can run but cant walk,what an I. I am very sorry to say that I failed again.nothing something anything everything 翻译成中文:I am worried that something bad happened to him 用中文翻译“I am worried that something bad has happened to him” I'm something that has four legs and only one foot.What am I'm something that can run but can't walk.What am