The manufacture of plastics requires a large quantity of heavy machines as well as knowledge of science. Today the greater part

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问题     The manufacture of plastics requires a large quantity of heavy machines as well as knowledge of science. Today the greater part of plastics is manufactured by the world’s great oil refineries and chemical works. Chemical works are factories which produce chemicals—a manmade liquids, gases and solid materials. The refineries and chemical works produce many different kinds of raw plastics, which are then taken to the tens of thousands of factories which made plastic products.
    Machines for making plastic objects are very different from those used for manufacturing articles of wood or metal or other natural materials. For raw plastics must first be softened by heat and then pressed into moulds. It is the moulds which give plastic objects their shapes. These moulds can be of any shape or size. And the same mould can be used over and over again. In fact one mould can produce many thousands of articles before it wears out. This is one of the reasons why plastic things are so cheap.  

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答案 生产塑料需要大量的有关重机器以及科学方面的知识。如今,较大部分的塑料都是由世界上大的炼油厂以及化工厂生产。化工厂指的是生产化学制剂(人工液体、气体以及固体物质)的工厂。炼油厂、化工厂生产各种各样的原塑料,然后这些原塑料被送往数以万计的工厂去生产塑料制品。 生产塑料制品的机器与那些生产木制的、金属的或其他天然材料的产品的机器截然不同。原因是原塑料必须先经过高温软化,然后再挤压成模具。就是这些模具使得塑料制品有了形状。这些模具的形状、大小各异,并且同样的模具可以反复使用。事实上,一个模具在它破损之前可以生产出成千上万件物品,这就是为什么塑料制品如此便宜的原因之一。

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