2013浙江高考英语 阅读 B 篇译文.doc

B Below is a selection from a popular science book. 以下选自一本著名的科学书籍 If blood is red, why are veins（静脉） blue? 如果血液是红的,为什么静脉是蓝色的呢？ Actually, veins are not blue at all. 事实上,静脉根本不是是蓝色的。 They are more of a clear, yellowish color. 它们更像是一种清澈的,偏黄色的一种颜色。 Although blood looks red when its outside the body, when its sitting in the vein near the surface of the skin, its more of a dark reddish purple color. 尽管血液看上去是红的当它流出身体外后，但是当它呆在靠近表皮的静脉里时，它更像是一种红的发紫的颜色。 At the right depth, these blood-filled veins reflect less red light than the surrounding skin, making them look blue by comparison. 在适当的深度，这些充满血液的静脉比周边皮肤显现出浅红色，相比之下，使它们看上去像蓝色。 Which works harder, you heart or your brain? 那个工作强度更大，你的心脏还是你的大脑？ That kind of depends on whether youre busy thinking or busy exercising. 这种就要取决于你是忙于思考还是忙于运动。 Your heart works up to three times harder during exercise, and shifts enough blood over a lifetime to fill a supertanker. 你的心脏工作强度在运动时强度高到3倍以上，接着传送足够的血液，终身都在填满一个超级油轮。 But in the long run, your brain probably tips it, because even when youre sitting still your brain is using twice as much energy as your heart, and it takes four to five times as much blood to feed it. 但从长远来看，你的大脑可能会推翻它，因为即使当你静静坐在那，你的大脑仍然正在使用比起你心脏多2倍多的能量，它用去4-5倍的血液量来完成。 Why do teeth fall out, and why dont they grow back in grown-ups? 为什么牙齿会掉，为什么成人长不出牙齿？ Baby (or “milk”) teeth do not last long; they fall out to make bigger room for bigger, stronger adult teeth later on. 乳牙不会长的太久；它们会脱落下来为了留下空间给之后的成人的大些，强健些的牙齿。 Adult teeth fall our when they become damaged, decayed and infected by bacteria. 成人的牙齿会脱落当它们受到损伤和被细菌给侵蚀。 Once this second set of teeth has grown in, youre done. 一旦第二幅牙长好，你的牙齿也就这么定了。 When theyre gone, they are gone. 当它们掉落后，就不会再长出来了。 This is because nature figures youre set for life, and what controls regrowth of your teeth switches off. 这是因为你自身设定下的自然定数，而控制你牙齿再一次长出的机制也随之关闭。 Do old people shrink as they age? 老人会随着年龄的增长而萎缩么？ Yes and no. 即对也不对。 Many people do get shorter as they age. 很多人的确会随着年龄的增