【英语时差8,16】为什么要给汽车换油？（下）

Heat and the motion of the engine break down the long chains into shorter chains and those chains are broken down even more. Old oil is better than no oil and will at least keep the engine from seizing up. But as the molecule¹ chains get shorter, the metal parts are more likely to come in contact with each other causing more wear inside your engine. When automobile² oil changes from the amber³ color it starts out with to the black color of old oil, that’s partly because it’s getting dirty, but it’s also undergoing chemical changes that prevent it from doing its job as well as it used to. If you change your oil yourself, save the old oil and take it to a service station or recycling center since used motor oil is very toxic⁴.

1 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

2 automobile   

n.汽车，机动车

参考例句：

• He is repairing the brake lever of an automobile.他正在修理汽车的刹车杆。
• The automobile slowed down to go around the curves in the road.汽车在路上转弯时放慢了速度。

3 amber   

n.琥珀；琥珀色；adj.琥珀制的

参考例句：

• Would you like an amber necklace for your birthday?你过生日想要一条琥珀项链吗？
• This is a piece of little amber stones.这是一块小小的琥珀化石。

4 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。