Three different kinds of engines have been used to move people and goods from one place to another. The first of these was the steam engine which was used for many years to move ships and trains. Then the internal combustion(燃烧) engine was invented. This is still used in many motor vehicles and in some aeroplanes. The diesel kind of internal combustion engines is used to move some trains and most ships. The most recent kind of engine is the jet engine. It is used in many aeroplanes. There are also a few small jet boats, and one day there may be jet cars and jet trains. The jet engine was invented by an Englishman, Frank Whittle, during the years 1928 to 1935. Whittle wanted an engine that would make aeroplanes fly faster.
An aircraft powered by an internal combustion engine has one or more propellers (螺旋推进器). Jet planes do not have propellers. This is because the jet engine works like a rocket.
Air is pulled into the front of the engine and burned with paraffin. A gas is formed. This gas expands and rushes out of the back of the engine. The force of the gas leaving the engine pushes the engine—and the aeroplane—forwards.
(210 words)
Choose the best answer:
1. What was the steam engine mainly used for?
A. To move ships, trains and aeroplanes.
B. To move motor vehicles.
C. To move aeroplanes.
D. To move ships and trains.
2. In what way is the jet engine better than the internal combustion engine?
A. It is cheaper to make.
B. It uses less fuel.
C. It does not need a propeller.
D. It can move aeroplanes faster.
3. When was the jet engine invented?
A. A few years ago.
B. Before the internal combustion engine.
C. About 70 years ago.
D. By Frank Whittle.
4. How does the jet engine work?
A. It turns a large propeller.
B. By internal combustion.
C. Expanding gas coming out of the engine pushes the engine forward.
D. High pressure steam.
5. What does the following picture show?
A. How an internal combustion engine works. B. How a jet engine works.
C. What an aircraft is. D. What a steam engine is.
参考答案：1.D 2.D 3.C 4.C 5.B
