Language activity

Exercise 1. Summarize your knowledge of the Degrees of Comparison. Use comparative or superlative forms of adjectives or adverbs in brackets.

1. Sight is (important) of the senses.

2. Schmidt-Cassegrain telescope is (popular) among amateur astronomers.

3. As the conversation went on, he became (talkative).

4. Travelling is becoming (expensive).

5. You look (beautiful) than usual.

6. Your accent is the (bad) in the class.

7. If you’re very hungry, you can have the (big) steak.

8. My mother’s driving is getting (dangerous) as the years go by.

9. It’s getting (hard) to find time for everything you want to do.

10. Reflecting telescopes can be (powerful) than refractors.

Exercise 2. Insert the prepositions in, into, of, on, at, by where it is necessary.

1. When light strikes ...a mirror ... an angle, it is reflected ... the same angle.

2. Light travels faster ... empty space than ... matter.

3. Diffuse reflection is the kind of reflection ... which we usually see objects.

4. Light rays bend when they go from air ... water.

5. Many optical devices are similar ... principle though their design and purpose may differ.

6. Absorption ... light results in the decrease in intensity.

Exercise 3. State the function and translate the verb "to be" according to the list given below.

1. смысловой глагол

2. вспомогательный глагол, образующий страдательный залог

3. входит в состав общепринятых выражений и не переводится

4. глагол-связка

5. that is = то есть

6. вспомогательный глагол, образующий группу продолженных времён

7. to be to = must

1. The working element of the ruby laser is a cylinder of pink ruby containing 0.05 per cent chromium.

2. In the commonly used laser configuration a ruby rod is surrounded by the coils of a helical flashlamp operated usually for a few milliseconds with an input energy of 1000 to 2000 joules.

3. The narrowing of the linewidth is due to effect of the resonant cavity formed by the mirror.

4. Why is it difficult for scientists to compare performance of different kinds of lasers?

5. One of the most characteristic features of the He-Ne laser is that the output power does not increase monotonically with discharge current but reaches a maximum and thereafter decreases.

6. This occurs when an impurity atom has acceptor properties, that is, can attract electrons.

7. Powder metallurgy is finding new applications in various industries – in electronics, aviation, machine-building, etc.

8. If we are to achieve the aim we must confine our attention to one point only.

Exercise 4. Pay attention to the different usage of the verb "to have".

1. смысловой глагол

2. вспомогательный глагол, образующий перфектную группу времён

3. have to = must

1. Commercial applications for gas-dynamic laser have not yet been found.

2. Our brief mention made here has been to estimate the conceptual interest of creating a population inversion by a gas-dynamic expansion.

3. Excimer laser has two peculiar but important properties.

4. The ordinary F-centers have a very low fluorescence quantum efficiency.

5. Let us indicate the difficulties that have to be overcome to obtain Х-ray laser operation.

Exercise 5. Read the sentences, state the function of provided and translate these sentences.

1. при условии, если (что);

2. давать, обеспечивать.

1. If this condition is not satisfied, however, laser action can still occur under pulsed operation provided condition mentioned above is fulfilled.

2. Copper vapor lasers provide the most efficient (~ 1%) green laser source so far available.

3. Polymethine dyes provide laser oscillation in the red or near infrared region.

4. Chemical lasers provide an interesting example of direct conversion of chemical energy into electromagnetic energy.

5. They are potentially able to provide either large output power or large output energy.

6. A resonator provides for a stronger coupling between the radiation and the excited atoms.

7. The elliptic cylinder is made of highly reflective material and is provided with reflective end plates.

8. The discharge is provided by radio-frequency generator which is usually operated in the 25-to-30 nm region.

9. Provided the temperature is changed, the force attracting electrons to atoms is also changed.