Iron has been known since prehistoric times. Although how humans first learned to extract the
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C) was first obtained from a source other than iron ore
D) was the most important discovery in humans history
E) was not known until 1200 BC
53- The author is almost certain that ............. .
A) iron ore was the only known source of iron until 1200 BC
B) the best examples of iron work were produced
during the Iron Age
C) the statement ―the metal of heaven‖ in ancient writings refers to iron
D) modern industry couldn‘t have developed without iron
E) how humans discovered iron ore will still be debated in the future
54- It is pointed out in the passage that ............. .
A) the method first used by man to extract iron from its
ore is well known today
B) other materials have not completely replaced iron in modern times
C) meteors are still the primary source of iron
D) iron alloys are much less important in industry than pure iron
E) at no time has iron been considered
as valuable as it is today
The question has often been asked why the Wright brothers were able to succeed in an effort in which
so many others had failed. Many explanations have been offered but three reasons are most often
cited. First, they were a team. Both men worked well together,
read the same book, located and
shared information, talked incessantly about the possibility of manned flight,
and served as a
consistent source of inspiration and encouragement to each others. They were also glider pilots.
Unlike some other engineers who experimented with the theories of flight, Orville and Wilbur Wright
experienced the practical side of their work by building and flying in kites and gliders. In addition,
the Wright brothers had designed more effective wings for the aeroplane than had been previously
engineered.
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