On February 9th, 2013, Sarah Darling was walking along the street when she met a homeless man named Billy Ray Harris. She reached into her change purse, emptied out all the coins she had and gave them to the homeless man. Neither of them realized that this small generous act would change their lives.

    Sarah didn't realize that she had given Billy not only all her change but also her diamond ring that she had put in her change purse earlier until the following morning. She and her husband, Bill Krejci, rushed to see if they could find Billy. The homeless man was not only in the same place, he also immediately returned the ring. The grateful couple paid him back for his honesty by emptying out their pockets of all the money they had.

    Bill Krejci, a web designer, felt that he needed to do something more for this amazingly honest man. So on February 18th, he set up a special page to raise money for him. In just four days, Billy received over $85,000 and there seems to be no end yet.

    That is not enough. Billy is living with a person who is generous instead of living in the streets. And that's not all—thanks to the news report, he got together again with his older brother, Edwin Harris, who he had been unable to find for 27 years.

    All the good luck is just because Billy did the right thing—returning something that did not belong to him.

材料一：

    荒漠化是由于干早少雨、植被破坏、大风吹蚀、流水侵蚀、土壤盐清化等因素造成的大片土壤生产力下降或丧失的自然（非自然）现象。荒漠化带来的危害是多重的，一方面影响生态气候，降雨量锐减，沙尘暴等恶劣天气频发；另一方面土地退化成沙地，无法发展农业，进而导致贫困，催生生态难民。被称作地球癌症的荒漠化是个全球性的难题，它在发展中国家蔓延速度更快，危害也更为突出。

    库布齐沙漠是距离北京最近的沙漠，曾是京津冀地区三大风沙源之一，被称为北京头上的一盘沙。而今，库布齐沙漠的荒漠化趋势得到遏制，荒漠化土地面积自1999年以来持续净减少，占总面积1/3的荒漠变成了绿洲，植被覆盖度则从16．2%加到了53%当地天气状况也在逐步好转，总体上库布齐的沙尘暴是治住了。在国内，企业参与治沙正成一种趋势。在库布齐沙漠中成长起来的中国亿利资源集团，25年投入30亿人民币，实施生态修复，“不用农药、不施化肥”，为沙漠农牧开发打下坚实的基础，并形成了一条具有亿利特色的绿色供应链。

材料二：

材料三：

    位于祁南园的塞罕坝林场是防治荒漠化的典型，从1962年开始种树治沙，经过55年的务力，林场职工让这里变成了112万亩茫茫林海。如今森林覆盖率由建场初期11．4%高到80%筹建塞罕坝等林场是很长一段时间政府治沙的主要模式，除改变当地自然风貌，保持水土之外，主要目的还是减轻京津地带的风沙危害。

    先治理容易的，再治理“远沙，大沙”，而容易治理的地方多与居民居住区相邻，植被容易被火灾或牲畜破坏。笔者发现即便在沙漠腹地种下的灌木丛也时常会引来放牧者，护林员要劝说对方离开。如果放任不管，多年辛苦种下的植物可能几天之内就被吃光。

    毗邻四大沙地之一的毛鸟素沙漠，遮天蔽日的黄沙让这里寸草不生，农业和畜牧业完全荒废，人穷到没有出路。32年前嫁到这里的般玉珍相信只有把树种活，人才能活下来。她卖掉家里唯一的羊种了600棵乔树苗，然而第一年过去只有十几棵存活，由此般玉珍认识到造林不能单一种植乔木，必须先用沙柳等灌木树种固定流沙。之后30多年里，她坚持造林7万亩，2011年这些树林被纳入国家公益林享受补贴。改善后的水土条件，还为她搞种植园旅游业提供便利。  国家菌草工程技术研究中心林占熺及其团队研发的被称为沙漠克星的茵草，被广泛应用于中国黄河中下游地区的生态屏障建设以及一些生态脆弱地区的防风固沙、水土流失治理和荒漠化治理中。现在，通过网络更多的人正在参与治沙，比如人们通过支付宝虚拟积分换取在阿拉善种下一棵梭梭树，至今植树量已超过76万棵。

    塞罕坝林场，库布齐、毛乌素沙漠是中国治理荒漠化的缩影，受到世界关注。2017年9月6日，联合国荒漠化大会在鄂尔多斯召开，大会认为中国经验值得推广到全世界。事实证明沙漠能够充分利用起来，沙漠这种给人类带来负面的东西，能够让它产生正能量。

（据央视网《新闻周刊》栏目整理）

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