CHOOSE THE WORD OR PHRASE ( A, B, C, OR D ) THAT BEST FITS THE BLANK IN THE FOLLOWING PASSAGE

Exercise 6 : Choose the word or phrase ( A, B, C, or D ) that best fits the blank in the following

passage.

Smog is the mixture of solid and liquid fog and smoke particles formed when humidity is high and the

air so (1)…… that smoke and fumes accumulate near their source. Before the (2)…… of the automobile,

most smog came from burning coal. In the 19

^th

century London, smog was so serve that street (3)…..

were turned on by noon because soot and smog (4)…… the midday sky.

Burning gasoline in motor vehicles is the main source of smog in most regions today. (5)…… by

sunlight, oxides of nitrogen and organic (6)……. react in the atmosphere to produce photochemical smog.

Smog contains ozone, a form of oxygen gas (7)….. up of molecules with three oxygen atoms (8)….. than

the normal two. Ozone in the lower atmosphere is a poison which is (9)…… by environmental officials to

determine the severity of smog. Whemn the ozone level is high, other (10)….. , including carbon

monoxide, are usually present at high levels as well.

1. A. silent B. quiet C. peace D. calm

2. A. age B. day C. year D. stage

3. A. candles B. lights C. lanterns D. signs

4. A. dark B. darkness C. darkened D. darkening

5. A. Energy B. Powered C. Managed D.Running

6. A. compounds B. complexes C. combines D. connects

7. A. do B. done C. make D. made

8. A. more B. better C. rather D. other

9. A. counted B. measured C. figured D. weighed

10. A. pollute B. pollution C. polluting D. pollutants