----- Nội dung dịch tự động từ ảnh -----
Today we take electricity for granted and perhaps we do not realize just how useful this discovery has
been. Steam was the first invention that replaced wind power. It was used to drive engines and was passed through
pipes and radiators to warm rooms. Petrol mixed with air was the next invention that provided power. Exploded in
cylinder, it drove a motor engine. Beyond these simple and direct uses, those forms have not much adaptability.
On the other hand, we make use of electricity in thousands of ways. From the powerful voltages that drive
our electric trains to the tiny current needed to work a simple calculator, and from the huge electric magnet in steel
works that can lift 10 tons to the tiny electric magnet in a doorbell, all are powered by electricity. An electric current
can be made with equal ease to heat a huge mass of molten metal in a furnace, or to boil a jug for a cup of coffee.
Other than atomic energy, which has not as yet been harnessed to the full, electricity is the greatest power
in the world. It is flexible, and so adaptable for any task for which it is wanted. It travels so easily and with
incredible speed along wires or conductors that it can be supplied instantly over vast distances.
To generate electricity, huge turbines or generators must be turned. In Australia they use coal or water to
drive this machinery. When dams are built, falling water is used to drive the turbines without polluting the
atmosphere with smoke from coal. Atomic power is used in several countries but there is always the fear of an
accident. A tragedy once occurred at Chernobyl, in Ukraine, at an atomic power plant used to make electricity. The
reactor leaked, which caused many deaths through radiation.
Now scientists are examining new ways of creating electricity without harmful effects to the environment
They may harness the tides as they flow in and out of bays. Most importantly, they hope to trap sunlight more
efficiently. We do use solar heaters for swimming pools but as yet improvement in the capacity of the solar cells to
create more current is necessary. When this happens, electric cars will be viable and the world will rid itself of the
toxic gases given off by trucks and cars that burn fossil fuels.
1. The author mentions the sources of energy such as wind, steam, petrol in the first paragraph to
A. suggest that electricity should be alternated with safer sources of energy
B. emphasize the usefulness and adaptability of electricity
C. imply that electricity is not the only useful source of energy
D. discuss which source of energy can be a suitable alternative to electricity
2. Before electricity, what was sometimes passed through pipes to heat rooms?
A. Gas.
B. Petrol.
C. Steam.
3. What does the author mean by saying that electricity is flexible?
A. It is cheap and easy to use.
C. It can be adapted to various uses.
4. What do we call machines that make electricity?
A. Voltages.
C. Generators or turbines.
B. It is used to drive motor engines.
D. It can be made with ease.
B. Electric magnets.
D. Pipes and radiators.
5. The main forms of power used to generate electricity in Australia are
A. atomic power and water
C. sunlight and wind power
6. The word "they" in the last paragraph refers
A. harmful effects
C. scientists
10. The best title for this passage
A. "Types of Power Plants"
C. "How to Produce Electricity"
B. water and coal
D. wind and gas
B. the tides
D. new ways
7. Electric magnets are used in steel works to
A. lift heavy weights up to ten tons
B. test the steel for strength
C. heat the molten steel D. boil a jug of water
8. The advantage of harnessing the power of the tides and of sunlight to generate electricity is that they
A. do not pollute the environment
B. are more reliable
C. are more adaptable D. do not require attention
9. Which of the following power sources causes pollution by emitting harmful gases?
A. Sunlight.
B. Petrol.
C. Water.
D. Hot wind.
could be.
B. "Electricity: Harmful Effects on Our Life"
D. "Why Electricity Is So Remarkable"
D. Wind.