【英语时差8,16】钻石能“永远”的秘密

Why Diamonds Really Are Forever Diamonds are forever they say, and this is why: diamonds are the hardest substance known to exist. Nothing would scratch or damage a diamond，While a diamond can scratch any other material on the earth. Everything is made from atoms, and these atoms are held together with chemical bonds. Something’s hardness is determined¹ by how tightly its atoms stick together. For example, when a diamond scratches against a piece of metal, metal atoms are torn loose while the atoms in the diamond stay snugly² in place. Why do the atoms of a diamond stick together so tightly? All atoms form only a limited number of chemical bonds at one time. For example, hydrogen atoms form only a single bond. Diamonds are made from carbon atoms which can form four bonds at once the maximum number for any atom. This means that each atom in a diamond is chemically linked to four of its neighbors in a rigid³ pattern. This is like tying something down with four pieces of rope instead of just one or two it makes each carbon atom very secure. There are other kinds of atoms that make four chemical bonds, but none of them form substances as hard as a diamond. This is because carbon is the smallest atom that can join to four of its neighbors. Its tiny size lets the carbon atoms snuggle more closely together than other atoms can, creating a firmer, harder material. It takes very high temperatures and pressures to pack carbon atoms tight enough to make a diamond. Without these, carbon atoms form materials like coal or graphite. Once they’ve been pressed into a diamond however, those carbon atoms are there to stay!

1 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

2 snugly   

adv.紧贴地；贴身地；暖和舒适地；安适地

参考例句：

• Jamie was snugly wrapped in a white woolen scarf. 杰米围着一条白色羊毛围巾舒适而暖和。 来自《简明英汉词典》
• The farmyard was snugly sheltered with buildings on three sides. 这个农家院三面都有楼房，遮得很严实。 来自《简明英汉词典》

3 rigid   

adj.严格的，死板的；刚硬的，僵硬的

参考例句：

• She became as rigid as adamant.她变得如顽石般的固执。
• The examination was so rigid that nearly all aspirants were ruled out.考试很严，几乎所有的考生都被淘汰了。