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    Here is a dog with a lantern(提灯) in his mouth. He is looking for his master(主人).

    Carlo, a lovely dog, had been taught to be useful. The roads, in the place where his master lived, were often so bad that it was not safe for any person to go out without a light on dark nights.

    So Carlo's master taught him to carry a lantern for him at night, and he did it as steadily(稳固地) as any boy could have done.

    Carlo never trotted(小跑) too far before his master so that the bright light of the lantern might guide his master's steps.

    When he came to a deep rut(车辙) or hole in the road, he would turn round to his master, seemed to say, “Take care, there is a hole here.''

    The dog's master lived about a mile from the town, and when he could not get home before dark, Carlo used to be sent to him with the lantern. Carlo usually knew where to go. He also knew the road which his master would take.

  But Carlo didn't always find his master right away. When he reached the town, he would run off to a house where his master often was. Still holding his lantern, he would scratch at the street-door with his feet and bark(吠叫), as much as to say, “Here am I, Master, with the lantern, are you ready for home?''

    Someone would perhaps come to the door and say, “Your master is not here.” Carlo would growl(嘟哝), seemed to say, “Then he is somewhere else, and I must find him.”

    He would then run off to one house after another, until he found his master, and then the two went home together.

SARS病毒的核酸在彻底水解后，得到的化学物质是（  ）

阅读下面的文字，完成下题。

    自古以来，哈尼人都是修沟造渠，引高山森林中的泉水来灌溉梯田，水沟开挖量巨大，必须投入大量的人力、物力才能完成，个人或村寨往往不能独立承担。哈尼人就户与户联合或者村与村联合，一起挖沟引水，通过出资的多少和投入人力的多少核定每个村寨、每一户的分水量大小。为了避免发生水纠纷，能够公平、公正、合理地分配水资源，哈尼人发明了分水木刻来进行分配。分水木刻，哈尼语称“欧斗斗”，它是选用板栗树、黑果树等材质坚硬的木料，在木料上刻出底部同样平整但宽窄度不一的凹槽的一根横木。

    尽管在哈尼人分水制发明和形成的时代并没有所谓“技术美”这样的名词出现，但实际上技术美的审美形态已经存在。技术美的内涵首先由技术品表现出来。人们创造任何一个技术品，都是具有实用性的。分水木刻作为分水制度的物质载体，是哈尼人为了对水资源进行合理分配而创造的工具，起到了准确计量各块梯田用水量的作用，可以说是我国最早使用的明渠流量计。分水木刻放置于每个水沟的分叉处，水要分几条沟就在分水木刻上刻几个凹槽，不同宽窄的凹槽决定了每个子水沟所灌溉梯田水量的大小，从而保证了每块梯田都能得到约定的用水量。哈尼人还以长方体为形状标准来制作分水木刻，长方形的设计，比其他形状更能防止水流的溢出，进一步提高了分水的准确性，且用料最省，是实现分水功能的最大化的典型形式。可见，分水木刻作为一种技术品，不仅具备了实用性，还具有了美的形式。

    分水制是指哈尼人经过村与村，户与户集体协商，根据挖沟时投入的人力、物力来确定每块梯田的水流量大小的民间制度。就其本质而言是商定分水木刻上凹槽宽度的一系列民间规约，是体现分水木刻功能的外在表现形式。分水制约定，投入多者，分水木刻凹槽宽，水流大；反之，投入少者，凹槽窄，水流小。为了确保凹槽计量单位的统一和准确，哈尼人还约定以某人的右手掌四指根部宽度为一基准单位，按照之前的协商结果对水流量进行分配，对用不了一个用水单位的，则缩减为一指、二指、三指进行细分，其中排除用小拇指宽度进行计量。照各家权益定制出的划有不同刻度的木刻，安放在各家田块的入水口，随着沟水流动调节了各家各户的用水，这样既公平合理而又有科学性。

    分水制虽然是一种抽象概念，但它与分水木刻有机联系在一起，构成了内容与其外在形象的相互统一，不可避免地以技术美的形态表现出来。分水制度经过了历史的考验，哈尼人代代相传，凝聚的已经不仅仅是生产技术，而是人的情感，对待分水制已经不仅是对实用功能的欣赏，更是对对象存在的审美。在现代农业科技飞速发展的今天，分水制还一直在沿用，它一方面使生产劳动的效率得以提高和完善；另一方面使分水的模式更趋于合理、更具有系统性和易于管理，给哈尼人带来了巨大的好处，符合哈尼人群体共同利益诉求。因此，分水制也渐渐和审美主体使用上的满意联系起来，从而获得了愉悦感和轻松感，构成了技术与审美的有机统一。