有学者说，世界上原本没有废物可言，只要处理得当，所谓的垃圾就会为人所用，大放异彩。换句话就是：“垃圾是放错了地方的资源。”如今，在“镍都”金昌，众多企业运用新技术、新工艺变“废”为“宝”，点“石”成“金”。这一事实蕴含的哲理是（  ）

已知，半径为4的圆中，弦AB把圆周分成1：3两部分，则弦AB长是____．

    John usually goes to school by bus. He leaves (离开)his house at seven and gets to school at about seven twenty. His school is on the hill.

    From Monday to Friday John usually has four classes every day. He likes English. He wants to be an English teacher. He hopes he will go to the USA to study English one day. On Sundays, he often goes to the library with his friends, but sometimes they go to see movies.