英语专业四级考试指南 test 8

　　Airplane Engines
In 1945, a new type of airplane engine was invented. It was much lighter¹ and more powerful than earlier engines, and enabled warplanes to fly faster and higher than ever. This type of engine was called the jet engine because it belows a large jet of hot air backwards² at high speed. The first airplane to use the new jet engine was built in Britain and it began carrying passengers in 1952. It had two jet engines and flew much higher than petrol-engine airplanes. At this height the air is thinner and very cold, and so the airplane can cut through the air more easily. However, the cabin has to be air-conditioned and has to be at normal pressure so that the passengers may eat, read and sleep in comfort.
Today all long distance airplanes have jet engines. The modern jet airplanes are very big and can carry hundreds of passengers on two different floors, which makes air travel much cheaper.

1 lighter   

n.打火机，点火器；驳船；v.用驳船运送；light的比较级

参考例句：

• The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。
• The lighter works off the car battery.引燃器利用汽车蓄电池打火。

2 backwards   

adv.往回地，向原处，倒，相反，前后倒置地

参考例句：

• He turned on the light and began to pace backwards and forwards.他打开电灯并开始走来走去。
• All the girls fell over backwards to get the party ready.姑娘们迫不及待地为聚会做准备。