“过去，人们不要说跨进沙漠，就是在田间也会遭到抢劫；如今即便穿过离尼罗河遥远的地区也平安无事。”材料主要反映了(    )

在下面一段文字横线处补写恰当的语句，使整段文字语意完整连贯，内容贴切，逻辑严密。每处不超过l2个字。

    二氧化碳是最主要的大气保温气体之一。大气中的二氧化碳浓度升高会导致全球变暖，造成天气干旱或旱涝不均，甚至可能造成海洋水位上升，淹没大量沿海城市，①____。然而，也有研究指出，②____：比如增加的二氧化碳可以给植物“施肥”，有利于植物的生长。但这必须有个前提，植物还活着!如果土壤被污染，③____，我们就失去了这些向大气中释放氧气的“氧气工厂”和“空气净化器”。

阅读短文，根据短文内容回答问题。
    We've all heard of mermaids. They are the beautiful half-human, half-fish creatures(生物). They have the head and body of a human and the tail of a fish. We also know that mermaids only exist in fairy tales. But where did all the stories about these creatures come from? If you have ever seen a manatee, then you might have an idea.
    Manatees, which are also called sea cows, are mammals(哺乳动物) that live in the sea. Since they are mammals, they have to swim up to the surface to breathe air. Many people believe that the story of the mermaid began with the ancient sailors who saw the manatees putting their heads out of the water to breathe. Because manatees are upright when they do this, it looks like they are standing. If a sailor saw a manatee doing this from far away across the sea, it is possible that the sailor would mistake the manatee for a creature that is half-human, half-fish.
Mermaids are described as having very long hair. This is probably because manatees like to swim up to the surface of the water in areas where there is sea grass. Manatees eat all kinds of plants in the sea, including sea grass. The sea grass around the manatee’s head when they eat could create a picture of long hair.

    Manatees also have powerful tails that are very similar to the fish-like tail of a mermaid. The sailors probably watched manatees come up for air and then swim back below the surface, using their paddle-shaped tails. This would explain why the sailors thought mermaids had fish-like tails.

照应所给文句的意思，续写一段话。

听高雅的音乐，可以陶冶人的性情，可以激励人的斗志，可以抚慰受伤的心灵，你看，____