急求:谜底是"书包"的谜语.

I have a friend.It has a big mouth,two long hands. It likes eating books.What am I'm the bag. 我有一个朋友，它有一张大嘴，两只长手，它喜欢吃书。谜底是书包

帆布兜，
知识库。
小时用，
大时无。
（打一学习物品）

http://www.baidu.com/s?cl=3&wd=%C3%D5%D3%EF+%C3%D5%B5%D7+%CA%E9%B0%FC

have a friend.It has a big mouth,two long hands. It likes eating books.What am I'm the bag. 我有一个朋友，它有一张大嘴，两只长手，它喜欢吃书。谜底是书包