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Варіант 3.

Petroleum gas is usually a mixture of several hydrocarbons
and exists in the subsurface as separate accumulations, in
association with oil accumulation, in solution in oil, and in
solution in formation water. Gas is compressible, and under certain
conditions of temperature and high pressure, some of the
components may be liquid in the subsurface (their physical
properties then being similar to those of oil). It is important as a
substance in its own right as a fuel and as a feedstock for industrial
chemical plants. It is also the prime source of energy in many oil
reservoirs. Methane is the dominant constituent of natural gas,
usually with smaller amounts of alkanes with higher carbon
numbers. A gas may be wet and contain liquid oil vapours, or dry.
Carbon dioxide is usually present as a contaminant; nitrogen is
found in some areas, notably the German North Sea. Sulphur is a
common contaminant that must be removed before the gas (or oil)
is used as a fuel. Most of the world’s commercial sulphur comes
from this source.

І. Choosing the Correct Definition for a Context:

Petroleum gas exists:

a) in the surface waters
b) at the industrial chemical plants
c) in the atmosphere
d) in the subsurface

II. Test Your Understanding of the Words:

In line 11 “dominant” means:

(a) subordinate (b) controlling

(c) prevailing (d) inferior