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Natural gas either occurs together with crude oil or forms separate deposits of gas alone. Decomposition of both animal and vegetable remains over a period of many centuries without air is the source of natural gas. A great volume of gas accumulates and penetrates into porous beds of sand, sandstones and limestones. In these beds gas can form natural deposits under great pressure. When a borehole reaches such a deposit the gas rushes up. This gas has to be collected from several boreholes with the help of pipelines over long distances. Russia has a gigantic network of pipelines.
Natural gas is an inflammable gas and consists of hydrocarbons with a very low boiling point. Methane ( CH4 ) makes up approximately 85 per cent of the typical natural gas. Ethane (C2 H6 ) can be present up to 10 % and propane ( C3 H8 ) up to 3 %.
Butane, pentane, hexane, octane and a few other gases may also be present. In contrast to crude petroleum natural gas has no distinct odour.
Little of natural gas we may use chemically ,most of it we use as a fuel for the production of both heat and energy. Like all gaseous fuels natural gas gives a great amount of heat. Natural gas is valuable also as an important chemical raw material for industry, as chemical technologists are able to obtain hydrogen, acetylene, carbon black and various chlorine derivatives.
Natural gas occurs mainly in Russia and some other CIS countries and in the United States where most of the extraction and utilization takes place. Before the war we utilized gas only at Baku and in the Carpathian Mountains. Since then they have discovered numerous new sources, for example , in the Ukhta (Russia) and Emba regions (Kazakhstan), near Saratov, Fergana (Uzbekistan), Samara, Volgograd and Grozny. In Europe they found rich deposits in Rumania and Italy, smaller ones in Austria and France. Germany also has several small but intensively worked fields.

Вставьте недостающие предлоги in, from, into, on, of, under, during

1. We'll have it...in April...on board the Vilnus.

2. ..Under. the navigating bridge and...in the wheel-house.

3. Who will take bearings ..of. the ship's position?

4. Can you plot the ship's course...on a chart?

5. Who will instruct you ...during  your shipboard training?

6. Do your engineers know how to repair the engine .in ..case of...trouble?

7. They certainly will learn how to load cargoes..from .quays and into... the ship's holds.

8. Will all your cadets have their training...on board ship's?

9. Not all...of them. Some...of them will have practice...in the ports.

1 we had taken an ice-cream before we left the ice-cream parlor.

2 I helped him to do the task after I had finished my work.

3 he had not practiced the song before he sang it in the programme.

4 she had met him before the party.

5 the plane had left by the time I go to the airport.

6 you had studied Italian before you moved to Rome.

7 he had never played football until last week.

8 she had established her company before 1998.

9 they had gotten engaged before last year.

10 I had fallen asleep before 8 o'clock.

11 I wished I had told the truth.

12 the boy wished he had asked another question.

13 I had just gone outside when it started to rain.

14 the bus had just left when we got to the stop.

15 he had just put the dog on the leash when we got there.

16 I had never seen such a beautiful sunset before I went to the island.

17 she had never been to the symphony before last night.

18 he understood the math test because he had lived there for 5 years.

19 I didn't have any cash because I had lost my purse.

20 I had been to Mexico once before.

21 if I had seen him, I would have told him the news.

22 she had lived in California before moving to Texas.

23 the cat had chased the bird before it flew out of the yard.

24 she had visited several doctors before she found out what the problem was with her hand.

25 we wished we had purchased the winning ticket.

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