And they come in their own very hard shell.

它们都有硬的外壳。

For one, they have a hard, mineralized layer on the outside.

首先，鳞片表面有硬的矿化层。

This cooling liquid formed a very hard rock known as granite.

这种冷却液体形成了一种硬的岩石，被称为花岗岩。

It's not even wooden; that's rock-solid.

门甚至不是木头做的；是硬的实心材质。

The nails on our fingers and toes are only parts of the skin which have grown very hard.

我们的手指与脚趾上的指甲, 只是长硬的一部分皮肤而已。

This material forms very hard ceramics that also find use in everything from car brakes to bulletproof vests.

该材料可制造硬的陶瓷，而这种陶瓷适用于从汽车制动到防弹背心等很多领域。

Well, the stone is a kind of very hard rock called granodiorite. It is dark grey and pink in color.

石碑由硬的花岗闪长岩制成。石碑的颜色为深灰色粉色。

Have you ever seen a diamond? It is a very bright, hard kind of stone, and very dear.

小朋友，你见过钻石吗？钻石，也叫金刚石，是一种光亮，硬的石头，价钱还特别贵。

She thinks it is a very hard cupboard!

她认为这是一个硬的橱柜！

Brazil nuts have very hard shells.

巴西果有硬的外壳。

It's almost like you have a very hard piece of rock on your skin.

这几乎就像你的皮肤上有一块硬的岩石。

It can be a soft material or it can be a very hard material.

它可以是柔软的材料，也可以是硬的材料。

It tastes like something really hard and it's been out for like 10 years.

- 它尝起来像硬的东西，已经出来了 10 年。

And I spent a month or so experimenting with PLA, which is a hard and scratchy, breakable material.

我花了一个月的时间用原生树脂做实验。这种材料的硬、粗糙、易折。

A few carnivorous eat very hard food, and have specialized adaptations for cracking bones or shells.

一些食肉动物吃硬的食物，并且有专门的适应能力来破解骨头或贝壳。

So these things are really tough, and the buildings they're in are probably hardened both inside and out.

所以这些东西硬，它们所在的建筑内外可能都加固了。

This is like a really hard plaque that discolors your teeth, and at this point, only a dentist would be able to get rid of it.

这就像是一种硬的牙菌斑，会让你的牙齿变色，这时，只有牙医才能将其清除掉。

" Coal" (coal) is a very hard, black substance that you dig out of the ground to use as fuel, to use for energy.

“煤” （煤炭）是一种硬的黑色物质，你从地下挖出来用作燃料， 用作能源。

There was a " pearl necklace." " Pearls" are not stones, but they are a very hard substance that you find in an oyster.

有一条“珍珠项链” 。 “珍珠”不是石头，而是一种硬的物质， 可以在牡蛎中找到。

Cobalt is a hard, shiny metal that is often mixed with other metals. It is very rare but extremely important to the production of batteries.

钴是一种硬、光亮的金属，经与其他金属混合存在。这种金属罕见，但对电池的生产极为重要。