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Questions 76 to 80 are based on the following passage:
Yellow fever is a disease of warm lands that is found mainly along theshore
of
the Atlantic Ocean. It was first noticed in the
Americas, but maywell have come
form
Africa
and
reached
the
New
World
with
or
soon
afterColumbus.
Until
about
fifty
years ago,
yellow fever was still one of themost feared
diseases in the United
States, where
many died in repeated out-breaks. An outbreak
which was to lead to
surprising
developments was onethat happened in Cuba during
the Spanish-American
War.
As a result, an army group under Major Walter Reed was sent there inJune, 1900
with
orders
give
special
attention
to
questions
concerningthe
cause
and
prevention of
yellow fever
Major Reed proved the truth
of an idea advanced in 1881by a Cuban doctor, that
the city type of mosquito passed on the
disease.
The
successful
result
of
these
experiments
gave
birth
to
another
andstill
more
important
idea:
kill
off
the
city
type
of
mosquitoes
and
therewill
be
no
more
yellow
fever. Fortunately these mosquitoes are
one of theeasiest types to destroy. They
are born in pools of quiet, warm
water,within a short distance to people's
home.
So to Havana came a General with orders from the United States Govern-ment
to
dry
up
these
pools.
He
carried
out
his
task
so
well
that
the
mos-quitoes
disappeared. With
them went yellow fever, never to return to
Havana.A few years
later the same
General successfully repeated this operation
inPanama and in this
way made possible
the building of the Panama Canal. Itall seemed so
simple. End
the mosquitoes: end the
disease. Man even beganto dream of getting rid of
yellow
fever from the world.
Meanwhile one question still remained unanswered. The city type of mosquitoes
carried the fever, without
doubt, but how? After many experi-ments, a member
of
the United States Army Yellow Fever
Commission decidedthat the disease must be
carried
by
something
too
small
to
be
seen.
Ofhis
own
free
will,
this
devoted
scientist
decided to allow
himself to bebitten by an infected mosquito. Then,
taking some
of his infected blood,he
injected it into three other members of the group
who
wanted to of the three got yellow
fever -- and recovered. This showed
that thedisease was carried by a virus
(2???) too small to be seen through the
microscopes of the day.
76. Yellow fever is found mainly around _______.
A) the Atlantic Ocean B) Any warm ocean
C) the Americas D) Any warm country
77. The outbreak which stirred the interest of the US Army was in _______.
A) Cuba B) Spain
C) Panama D) the United States
78. One of the reasons that yellow fever was defeated was that _______.
A) some people were willing to sacrifice themselves for others
B) doctors were well trained