Exercise 29. Read the text quickly and choose the best title, A, B, or C
A. The history of cabling and telecommunications.
B. A short introduction to optical fibres.
С. Uses of glass in industry and technology.
Optical fibres started to replace some uses of copper cables in the 1970s. They are made from glass and are usually about 120 micrometres in diameter. Some of the most common everyday uses are in telecommunications, close-circuit television (CCCTV), and cable television.
1____________________________Optical fibres carry signals more efficiently than copper cable and with a much higher bandwidth. This means that fibres can carry more channels of information over longer distances.
Optical fibre cables are much lighter and thinner than copper cables with the same bandwidth. This means less space is needed in underground cabling ducts.
It is difficult to steal information from optical fibres. They are not harmed by electromagnetic interference, for example from radio signals or lightning. They don't ignite so they can be used safely in flammable atmospheres, for example in petrochemical plants.
4____________________________ Optical fibres are more expensive per metre than copper. However, one optical fibre can carry many more signals than a single copper cable and the longer transmission distances mean that fewer expensive repeaters are required. Also, copper cable uses more electrical power to deliver the signals.
Optical fibres can't be spliced as easily as copper cable. Employees need special training to handle the expensive splicing and measurement equipment.
Exercise 30.Read the text again and match the headings (A-E) with the paragraphs (1-5).
A Training and skills D Price
B Size and weight E Capacity
Exercise 31. Which paragraphs describe advantages of optical fibres and which describe disadvantages?
Exercise 32. Complete the definitions (1-9) below with the highlighted words in the text.
1. A ________ is one millionth of a metre.
2. The _______ is the distance across a circle.
3. A ________ substance is one that burns easily.
4. ______ means joining the ends of two cables together.
5. To _________ means to start to burn.
6. _________ are tubes for carrying cables.
7. _______ is a common short way of saying 'for each'.
8. ____________means to touch with your hands.
9. ___________ means in a way that produces a good result and doesn't waste time, energy, or resources.
Exercise 33. Write two advantages and two disadvantages of using optical fibres instead of copper cable. Compare your ideas with the rest of the class.
Exercise 34. Use the Internet, magazines, or newspapers to find out about another interesting invention of the last twenty years. Try to find out two advantages and two disadvantages of the invention and tell your class. Decide who found out about the most interesting invention.
Text 6. Big is the Best
Exercise 35. Before you start:
Work in pairs. You have one minute. How many different dams or tunnels can you think of? Compare your answers with the rest of the class.
Exercise 36. Read the text quickly and decide which structure it describes.
a) The Hoover Dam
b) The Arlberg Tunnel
с) The Channel Tunnel
d) The Golden Gate Bridge
The ... is between Britain and France. It's more than 20 kilometres long. It was built by British and French engineers. They started on opposite sides and met in the middle under the sea. They used specially-designed tunnel boring machines (TBMs) to dig the tunnels through the rock under the seabed. TBMs are enormous machines for digging tunnels. The machines used to dig the main tunnels were about 8.5 metres in diameter and 250 metres long. Work started in 1987 and the teams met under the seabed in 1991. It is a rail tunnel. The first passenger train went through in 1994.
Exercise 37. Read the text again and answer the questions (1-9) below.
1. Where is it?
2. What is it?
3. How long is it?
4. Who built it?
5. How did they build it?
6. What are TBMs?
7. How big are TBMs?
8. How long did it take to build?
9. When did it open?
Exercise 38. First, underline the question words in Exercise 3. Then use them to complete these questions.
1. _____ many Roman roads are there in Europe?
2. _____ designed St Paul's Cathedral in London?
3. _____ is the name of the famous bridge in San Francisco?
4. _____ was the Eiffel Tower built?
5. _____ is the Corinth Canal?
Exercise 39. Complete the texts by putting one word in each space. Use the words in the box. Check the meaning of any new words in the glossary or your dictionary.
The Panama Canal is a 64km waterway (1)__________ the Atlantic and Pacific Oceans. Before the canal was opened, ships had to travel thousands of miles (2) ____________ South America. To build the canal, engineers had to dam a major river, and dig a channel (3) ______________ a mountain ridge.
Tower Bridge is an openable bascule bridge, designed by Horace Lones in 1886. It goes (4) ___________ the River Thames in London. Thousands of vehicles drive (5) ________ it every day. Tall ships cannot pass (6) _____ Tower Bridge, instead, the roadway parts and lifts to let them through.
Exercise 40. Write questions about a building, tunnel, or dam. Use who, what,when, where, and how. Make sure you know the answers!
For example: How old is it? Where is it?
Exercise 41. Work with a partner. Ask and answer the questions you wrote in Exercise 6.
Exercise 42. Find out about a major new engineering project. Where is it? What will it do? What problems do the engineers have to solve to build?
Text 7. Gadgets
©2015-2020 megaobuchalka.ru Все материалы представленные на сайте исключительно с целью ознакомления читателями и не преследуют коммерческих целей или нарушение авторских прав. (1072)
Почему 1285321 студент выбрали МегаОбучалку...
Система поиска информации
Мобильная версия сайта
Нет шокирующей рекламы