【英语时差8,16】史前的牙签

If asked to imagine the first prehistoric¹ tools, crafted and used by our early, hominid ancestors, you'd probably think of crude knives or spear heads, chipped from stone.   You probably aren't aware of another human innovation that might be just as old. Today we'll learn about the two million year history of the toothpick, possibly one of humanity's oldest tools.

Early stone tools, like knives and scrapers, are easy for anthropologists to learn about because these items are still around. Even after two million years, a chipped stone tool is still going to be there when you dig it up. Toothpicks, however, are another story. Made from splinters of wood, thorns, or bone fragments, these can rot and crumble³ away over time, leaving no recognizable trace. If this is so, how can an anthropologist² look at a two million year old fossil site and claim that these early pre-humans picked their teeth?

It's certain that no toothpick will ever last two million years, but this isn't the case with teeth. In fact, fossil teeth are the most durable⁴ remnants that anthropologists work with, and some of these ancient teeth display a curious set of grooves⁵. Although these might have been caused by tooth decay, a close examination of the marks seems to indicate that the grooves were worn by repeated toothpicking--probably to alleviate⁶ the pain of gum disease. Indeed, these fossil grooves match the toothpick grooves in the teeth of several modern aboriginal⁷ populations.

It's enough to warm every dentist's heart: The first tools weren't just for preparing food, hunting, or fighting. They might have been used for dental hygiene⁸ as well.  

1 prehistoric   

adj.（有记载的）历史以前的，史前的，古老的

参考例句：

• They have found prehistoric remains.他们发现了史前遗迹。
• It was rather like an exhibition of prehistoric electronic equipment.这儿倒像是在展览古老的电子设备。

2 anthropologist   

n.人类学家，人类学者

参考例句：

• The lecturer is an anthropologist.这位讲师是人类学家。
• The anthropologist unearthed the skull of an ancient human at the site.人类学家在这个遗址挖掘出那块古人类的颅骨。

3 crumble   

vi.碎裂，崩溃；vt.弄碎，摧毁

参考例句：

• Opposition more or less crumbled away.反对势力差不多都瓦解了。
• Even if the seas go dry and rocks crumble,my will will remain firm.纵然海枯石烂，意志永不动摇。

4 durable   

adj.持久的，耐久的

参考例句：

• This raincoat is made of very durable material.这件雨衣是用非常耐用的料子做的。
• They frequently require more major durable purchases.他们经常需要购买耐用消费品。

5 grooves   

n.沟( groove的名词复数 )；槽；老一套；（某种）音乐节奏v.沟( groove的第三人称单数 )；槽；老一套；（某种）音乐节奏

参考例句：

• Wheels leave grooves in a dirt road. 车轮在泥路上留下了凹痕。 来自《简明英汉词典》
• Sliding doors move in grooves. 滑动门在槽沟中移动。 来自《现代汉英综合大词典》

6 alleviate   

v.减轻，缓和，缓解(痛苦等)

参考例句：

• The doctor gave her an injection to alleviate the pain.医生给她注射以减轻疼痛。
• Nothing could alleviate his distress.什么都不能减轻他的痛苦。

7 aboriginal   

adj.（指动植物）土生的，原产地的，土著的

参考例句：

• They managed to wipe out the entire aboriginal population.他们终于把那些土著人全部消灭了。
• The lndians are the aboriginal Americans.印第安人是美国的土著人。

8 hygiene   

n.健康法，卫生学 （a.hygienic）

参考例句：

• Their course of study includes elementary hygiene and medical theory.他们的课程包括基础卫生学和医疗知识。
• He's going to give us a lecture on public hygiene.他要给我们作关于公共卫生方面的报告。