阅读下面材料，回答问题。

       发展中国家经济发展水平低，既有自身的原因，也有外部的原因。就其自身而言，经济基础太差；人口增长太快，每年新增的国民生产总值大多被新增人口所消费；内部地区差异大；教育水平低，法制不够健全以及政治、经济和社会结构不适应等都对国家经济发展起不同的制约作用。

就外部环境而言，旧的经济秩序还没有被打破，在国际贸易中，发展中国家仍处于不利地位，很多发展中国家主要出售石油、矿石、木材、橡胶等原料，这些产品往往价格较低。发达国家利用从发展中国家购买的原料，制造汽车、轮船、飞机、高档用品等价格较高的产品，并把它们销售到世界各地。这样，发达国家赚到的钱多，发展中国家赚到的钱少。

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    Where there is a will(意志), there is a way. The secret of s____  is not much money but a strong will. In other words, a man can't w____   without a strong will. It is quite clear that there is nothing d____ in the world. If a person makes up his mind to do it, he will certainly r____ his goal. A student should r____  the following duties: we s____ care about our parents; we have to study as h____  as possible, we must be honest and keep our words as well. E____  of us should receive good education. Our parents send us to school to let us get k____ and wish us to be a hard-working and successful person in the future. So when we fail, don't lose heart. Keep on working u____ we succeed. Make sure nothing could prevent you from trying.