英国学生科学读本 第64期:红色金属--铜(2)

 　　Copper¹ can be rolled or hammered out into thin sheets, and so we say that it is malleable². It can also be easily drawn³ out into wire, and for this reason we call it ductile⁴. Sheet copper is much used for covering the bottoms of ships, and for making kettles and saucepans and many other household articles.

　　经过碾压与捶打，人们就可以把铜制成薄片。因此，我们说，这种金属具有可锻性。通过拉伸，人们就可以获得铜线，因此我们说铜具有延展性。铜片可以用于覆盖船底以及制造水壶、炖锅与其他居家物品。

　　Copper is a good conductor of electricity—that is, it allows electricity to pass along it very easily. When electric lights or electric bells are put up, copper wire is always used. The cables which are placed on the bottom of the sea to carry telegraph messages from one country to another have copper wires running through them.

　　铜是很好的导电介质，也就是说，电流可以轻易通过这种金属。人们在电灯与电铃中总会使用到铜线。用于在不同国家之间传送电报信息的海底电缆也使用到了铜线。

　　Copper does not rust⁵ or tarnish⁶ so quickly as iron when exposed to the air. But if we heat a piece of sheet copper in a clear fire, we shall find that the surface turns black, from the copper rust which forms all over it.

　　与铁相比，如果暴露在空气之中，铜并不会那么快生锈与褪色。然而，如果我们使用明火对铜片进行加热，那么就会发现其表面从铜锈处开始变黑。

　　Copper is harder than lead, for we cannot scratch it with our finger-nail as we can scratch lead. But it is not so hard as iron, for it is easily scratched by an iron nail. Copper takes on a fine polish, and the surface of a piece of clean and polished copper is very bright.

　　铜的硬度比铅要高，因为与铅不同，我们无法用指甲在铜的表面刮出痕迹。不过它的硬度又比不上铁，因为我们可以用铁钉轻松地在铜的表面留下刮痕。铜的抛光性很好，一块经过抛光的纯铜表面能够呈现明亮的光泽。

1 copper   

n.铜；铜币；铜器；adj.铜(制)的；(紫)铜色的

参考例句：

• The students are asked to prove the purity of copper.要求学生们检验铜的纯度。
• Copper is a good medium for the conduction of heat and electricity.铜是热和电的良导体。

2 malleable   

adj.(金属)可锻的;有延展性的；(性格)可训练的

参考例句：

• Silver is the most malleable of all metals.银是延展性最好的金属。
• Scientists are finding that the adult human brain is far more malleable than they once thought.科学家发现成人大脑的可塑性远超过他们之前认识到的。

3 drawn   

v.拖，拉，拔出；adj.憔悴的，紧张的

参考例句：

• All the characters in the story are drawn from life.故事中的所有人物都取材于生活。
• Her gaze was drawn irresistibly to the scene outside.她的目光禁不住被外面的风景所吸引。

4 ductile   

adj.易延展的，柔软的

参考例句：

• Steel in this class is tough，ductile and easily machined.这种钢强韧，延展性好，而且容易加工。
• The metal is very hard and strong and less ductile than before.金属会非常坚硬、坚固，并比以前减少了韧性。

5 rust   

n.锈；v.生锈；(脑子)衰退

参考例句：

• She scraped the rust off the kitchen knife.她擦掉了菜刀上的锈。
• The rain will rust the iron roof.雨水会使铁皮屋顶生锈。

6 tarnish   

n.晦暗，污点；vt.使失去光泽；玷污

参考例句：

• The affair could tarnish the reputation of the prime minister.这一事件可能有损首相的名誉。
• Stainless steel products won't tarnish.不锈钢产品不会失去光泽。