- People always have been eager to explore their environment and to discover the ends of the earth. Some years ago, however, many people believed that the unknown world was occupied by ferocious peoples and terrifying monsters. Their fears made them
Your answer:
move to new and better lands.
become successful hunters.
seek dangerous adventures.
content to stay at home.
- "Smog," or the air that is filled with dirt and smoke, settles on a certain city much of the time. The exhaust from thousands of cars and vans has no escape since the city is rimmed by mountains on one side and by the ocean on the other. The cool air from the ocean is close to the ground and thus prevents the warm air from rising high enough to go over the mountains. In other words, the city lies in a kind of air pocket, and the air currents move back and forth between
Your answer:
north and south.
the city and the suburbs.
the east coast and the west coast.
the mountains and the ocean.
- Power lawn mowers for use in cutting grass should travel at about four kilometers an hour. The operator walking behind the mower will not find this speed
Your answer:
adequate.
relaxing.
tiring.
constant.
- The earliest submarines could not use their diesel engines when running underwater because the engines would soon use up all the oxygen in the air, leaving none for the crew to breathe. This meant that the ships could not
Your answer:
make long voyages.
have large crews.
carry enough fuel.
stay submerged very long.
- Although babies born this year have a life expectancy at birth much greater than babies born a century ago, people who are now fifty years old can expect to live longer than their great-grandparents at age fifty could have expected to live. Medicine has made impressive progress against diseases of youth, but it has made less headway against
Your answer:
diseases of old age.
diseases prevalent a century ago.
very serious illnesses.
preventable accidents.
- There is little danger that this house will be destroyed by fire, for the materials of which it is made are
Your answer:
durable.
sturdy.
noncombustible.
expensive.
- Stamp collecting is such a popular hobby around the world that some governments issue many special stamps to profit from this huge market for them. A few small countries, like San Marino, make much of their government income by issuing stamps attractive to
Your answer:
governments.
officials.
postmasters.
collectors.
- Birds eat a great deal; in fact, they seem always to be pecking at something. Most birds, however, do not store food against a time of shortage as squirrels do. When birds find food, they eat; when the supply is exhausted, they go
Your answer:
home.
to their nests.
north again.
somewhere else.
- The young novelist was pleased to hear that her book had been praised by a critic whose judgment was universally regarded as
Your answer:
extravagant.
misleading.
superior.
prejudiced.
- Life insurance companies report that among people forty-five to fifty years of age, the lowest death rate occurs among those whose weight is from 4.5 to 9 kilograms below average. Underweight seems to be associated with
Your answer:
longevity.
occupation.
sex.
medicine.