Exercise 4 . Open the brackets.

    1. I don’t want them (to think) you were wrong. 2. I’d rather not (to go) home that way. 3. I had not seen Jimmie (to lose) his temper before. 4. I want (to begin) (to earn) my own money. 5. I never let him (to be) angry. 6. He wants (to congratulate) you in person. 7. I don’t like (to see) men (to cry). 8. There was nothing (to do) but (to watch) films on the sofa all day long. 9. It’s very interesting (to hear) you (to say) that. 10. I have not done much for you. You might (to ask) much more at that time.

 

Exercise 5. Fill in the gaps with the words from the box.

ask for   buy   catch     drive     finish   meet    learn   wait for

 

1. Jason got up early … Mark to the station. 2. I was late, so I ran … my bus. 3. Ann wrote to me … Andy’s address. 4. I sat in the waiting room … the doctor. 5. Lesley has gone to the airport … his uncle. 6. I went to town on Saturday … a present for my cousin’s birthday. 7. I stayed up late last night … my English homework. 8. Katya went to Beijing … Chinese.

 

Exercise 6. Translate the following sentences into English.

1. Нам відомо, що вони використовували нове джерело інформації. 2. Я думаю, що вони проведуть всебічний аналіз цього процесу. 3. Для того, щоб це відбулося, температура повинна бути достатньо високою. 4. Ми змусили його вирішити це рівняння. 5. Дозвольте мені першому виступити з доповіддю. 6. Професор закінчив викладати оптику в 2002 році. 7. Марія Кюрі першою відкрила радій. 8. Забезпечити всіх студентів необхідною літературою є, на жаль, нелегкою задачею. 9. Ми хочемо, щоб студенти оформлювали свої курсові і дипломні роботи із урахуванням вимог атестаційної комісії. 10. Предмет виявився настільки цікавим, щоб присвятити йому наше подальше дослідження.

 

Exercise 7. Study the following words and word combinations.

abrasion (n) – стирання; знос

abrasion resistance – зносостійкість

appropriate (adj) – підходящий; придатний; відповідний

bounce (v) – підплигнути; відскакувати

campus (n) – кампус, територія університету

cladding (n) – зовнішня оболонка, покриття

core (n) – центр, серцевина, ядро, найбільш важлива частина

fiber (n) – волокно, фібра, нитка

jacket (n) – чохол, кожух

shield (v) – захищати, вкривати, екранувати

span (v) – простягатися (у просторі і часі)

strand (n) – жила кабелю

terrestrial (adj) – наземний; той, що знаходиться на поверхні землі

tunnel (v) – проходити; прокладати тунель; пробивати

wire (n) – проволока, кабель

 

Exercise 8. Fill in the gaps with the words given above.

1. The engineers had to … through solid rock. 2. … is used to cover hot pipes to reduce loss of heat. 3. She lives on …, it means within main university area. 4. The operation which … nine countries, resulted in 200 arrests. 5. The box was fastened with a rusty …. 6. The book was written in a style … to the age of the children. 7. Issues of the environment are at the … of our policies. 8. Diamonds have extreme resistance to …. 9. … optics means using special types of materials to send information in the form of light signals. 10. … animals live on the land or on the ground rather than in water, in trees or in the air.

 

Exercise 9. Before you read the text, answer the following questions.

· What ways of transmitting information do you know?

· How do they work?

· Which one is the most effective?

· Which one is the easiest to produce?

 

TEXT 1

 

Fiber-Optic Technology

In recent years fiber optics has become apparent to be steadily replacing copper wire as an appropriate means of communication signal transmission. Fiber optic systems are currently used most extensively as the transmission link between terrestrial hardwired systems. They span the long distances between local phone systems as well as other system users which include cable television services, university campuses, office buildings, industrial plants, and electric utility companies.

A fiber-optic system can generally be seen as a system with three main components: a transmitter, a transmission medium and a receiver. As a model it is similar to the copper wire system to be replaced by fiber optics. The difference is that fiber optics uses light pulses to transmit information down fiber lines instead of using electronic pulses to transmit information down copper lines. Looking at the three main components in the fiber optic chain will give a better understanding of how the system works in conjunction with wire based systems.

At the head end of the chain is the transmitter. This is the place of origin for information coming on to fiber optic lines. The transmitter accepts coded electronic pulse information coming from copper wire. It then processes and translates that information into equivalently coded light pulses. A light-emitting diode (LED) or an injection-laser diode (ILD) can be used for generating the light pulses. Using a lens, the light pulses are tunneled into the fiber-optic medium where they transmit themselves down the line.

Light pulses move easily down the fiber-optic line because of a principle known as total internal reflection. This principle of total internal reflection states that when the angle of incidence exceeds a critical value, light cannot get out of the glass; instead, the light bounces back in. When this principle is applied to the construction of the fiber-optic strand, it is possible to transmit information down fiber lines in the form of light pulses.

There are generally five elements to make up the construction of a fiber-optic strand, or cable: the optic core, optic cladding, a buffer material, a strength material and the outer jacket. The optic core is the light carrying element at the center of the optical fiber. It is commonly made from a combination of silica and germanium. Surrounding the core is the optic cladding made of pure silica. It is this combination that makes the principle of total internal reflection possible. The difference in materials used in the making of the core and the cladding creates an extremely reflective surface at the point in which they interface. Light pulses entering the fiber core reflect in the core cladding interface and thus remain within the core as they move down the line.

Surrounding the cladding is a buffer material used to help shield the core and cladding from damage. A strength material surrounds the buffer, preventing stretch problems when the fiber cable is being pulled. The outer jacket is added to protect against abrasion, solvents, and other contaminants.

Once the light pulses reach their destination they are channeled into the optical receiver. The basic purpose of an optical receiver is to detect the received light incident on it and to convert it to an electrical signal containing the information impressed on the light at the transmitting end. To put it in other words the coded light pulse information is translated back into its original state as coded electronic information. The electronic information is then ready for input into electronic based communication devices such as a computer, telephone or TV.