Usually, age is determined by physical characteristics, such as teeth or bones.
通常说来，年龄是通过生理特征确定的，譬如牙齿或骨骼。
A protective covering, structure, or organ of an animal or a plant, such as teeth, claws, thorns, or the shell of a turtle.
防御器官动物或植物的防护层，结构或器官，如牙齿，爪子，荆棘或乌龟的壳。
First, the defensive posture, where the body is fluffed up to appear larger or weapons such as teeth and claws are flashed.
首先是防御姿态，如果身体上有羽毛的话就竖起来，或是亮出牙齿和爪子等武器。
Failure mode of tooth surface is varied such as teeth surface pitting, teeth wear, teeth bonding and teeth plastic deformations and so on.
齿面常见的失效形式有齿面点蚀、齿面磨损、齿面胶合和齿面塑性变形等。
It had feathers and other traits of living birds but also vestiges of a reptilian past, such as teeth in its mouth, claws on its wings, and a long, bony tail.
始祖鸟拥有羽毛，它身上既有现代鸟类的特征，也有远古爬行动物的痕迹，例如口中有牙齿，翅膀上有爪子，还有一条硕长的骨质尾巴。
Until now, crime scene investigators have depended on the availability of specific body parts, such as teeth, bones or ligaments, for estimating the age of otherwise unidentifiable persons.
到目前为止，犯罪情景研究院主要依赖于特殊的身体器官，比如牙齿，骨头和韧带来估计一个未出现的人的年龄。
Human beings needed to use tools because they did not have sharp teeth like other meat-eating animals, such as lions and tigers.
人类需要使用工具，因为他们没有像其他食肉动物如狮子和老虎那样锋利的牙齿。
They found that the average person's mind wandered most frequently about 65% of the time during personal activities, such as brushing their teeth and combing their hair.
他们发现，一般人在刷牙、梳头等个人活动中最常走神，约有65%的时间在走神。
Many carnivorous dinosaurs have ambiguous features, such as "peg-like" teeth at the front of the mouth, or no teeth at all.
许多食肉恐龙的特征并不是很明显，例如，要么在嘴的前部有“钉状牙齿”，要么就根本没有牙齿。
"We can rule out that the dogs simply distinguish between the pictures based on a simple cue, such as the sight of teeth," said study author Corsin Muller.
研究作者科辛·穆勒说：“我们可以排除狗只是根据简单的线索来区分图片，比如看到牙齿。”
If you do daily "self-control exercises", such as making your bed or brushing your teeth, you'll improve your overall willpower.
如果你每天都做“自制练习”，比如整理床铺或刷牙，你的整体意志力就会得到提高。
Discovering direct evidence of what a fossil animal ate, rather than having to infer it from details such as the shape of its teeth, is always valuable.
发现一种动物以何为食的直接证据非常的有价值，我们不用再从它们的牙齿形状来推测它们吃什么了。
Saliva acts as a barrier, protecting the teeth by neutralising acidic foods such as oranges, and the acid produced by bacteria as they break down foods.
而唾液正像一道保护牙齿的屏障，把橘子等酸性食物以及细菌分解食物产生的酸性物质中和掉。
The dinosaurs weren't exactly sucking, but it's thought that many simply tore off plant material, such as leaves, with their teeth and swallowed this mass whole.
恐龙并没有像吸尘器那样“吸”，但它们通常用牙齿扯下一段植物——比如说叶子，然后整个吞下。
But many theropod dinosaurs have ambiguous features, such as peg-like teeth at the front of the mouth, or no teeth at all.
但是，许多食肉恐龙的特征并不是很明显，例如：要么在嘴的前部有“钉状牙齿”，要么就根本没有牙齿。
Many things we do on a regular basis can contribute to stained teeth, such as drinking coffee, tea, cola and red wine or smoking.
我们平时经常做的一些很普通的事情都会给牙齿留下斑点，比如说喝咖啡，茶和可乐，以及红酒，或是抽烟。
We can also guess that such a toothbrush may hurt the man's teeth as well as his mood, inconveniencing him greatly.
我们可以猜到这支牙刷不仅可能伤害这个人的牙齿，也破坏了他的心情，给他带来了很多不便。
The Greeks, and then the Romans, improved the recipes for toothpaste by adding abrasives such as crushed bones and oyster shells, which were used to clean debris from teeth.
先是希腊人，然后是罗马人，将牙膏的配方加以改进。他们添加了一些磨料如碎骨和牡蛎壳，用来清除牙齿上的污垢。
Low concentrations are good for teeth, but excessive concentrations can lead to debilitating disease, such as skeletal fluorosis, which has devastated some communities.
低浓度对牙齿有益，但浓度过高则可能导致使人衰弱的疾病，比如氟骨症，一些社区因此而成为一片废墟。
For example, parents can schedule activities — such as brushing teeth, taking a bath, or reading a story — that assist the transition to bedtime.
例如，父母可以通过安排诸如刷牙、洗澡或朗读故事等方法来帮助孩子及时就寝。
Even routine daily actions, such as brushing one's teeth, turning the pages of a newspaper or dressing a small child would easily defeat today's robots.
哪怕是些简单的日常动作，例如刷牙、翻报纸、给小孩子穿衣服都能难倒现在的机器人。
That is interesting. Discovering direct evidence of what a fossil animal ate, rather than having to infer it from details such as the shape of its teeth, is always valuable.
比起根据其牙齿形状等细节来推测出结果，找出古生物吃什么的直接证据是有价值的。
Fierce animals such as lions and tigers have sharp teeth and claws.
凶猛的动物，例如狮子和老虎有锋利的牙齿和爪子。
Un, lifestyle choices such as what we choose to eat and drink, and how we look after our teeth can, over time, create a smile we are less than happy with.
但是，平常我们生活中吃的、喝的东西慢慢地就会在牙齿上留下牙渍，常常使我们不能开怀大笑，应该怎么保护牙齿呢。
ScienceDaily (Sep. 6, 2009) - it's been a mystery: how can our teeth withstand such an enormous amount of pressure, over many years, when tooth enamel is only about as strong as glass?
科学日报(2009年9月6日)——当牙齿上的牙釉质大约只有玻璃般强硬时，我们的牙齿这么多年来是怎样经受住一个如此巨大的压力的？
ScienceDaily (Sep. 6, 2009) - it's been a mystery: how can our teeth withstand such an enormous amount of pressure, over many years, when tooth enamel is only about as strong as glass?
科学日报(2009年9月6日)——当牙齿上的牙釉质大约只有玻璃般强硬时，我们的牙齿这么多年来是怎样经受住一个如此巨大的压力的？
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