【每日逻辑链练习贴】【逻辑5-3】【OG10】

balapupu

                                   既然作文木有了~~那我们就还是5道逻辑呗~~
49. A milepost on the towpath read “21” on the side facing the hiker as she approached it and “23” on its back.
She reasoned that the next milepost forward on the path would indicate that she was halfway between one
end of the path and the other. However, the milepost one mile further on read “20” facing her and “24” behind.
Which of the following, if true, would explain the discrepancy described above?
(A) The numbers on the next milepost had been reversed.
(B) The numbers on the mileposts indicate kilometers, not miles.
(C) The facing numbers indicate miles to the end of the path, not miles from the beginning.
(D) A milepost was missing between the two the hiker encountered.
(E) The mileposts had originally been put in place for the use of mountain bikers, not for hikers.


50 Airline: Newly developed collision-avoidance systems, although not fully tested to discover potential
malfunctions, must be installed immediately in passenger planes. Their mechanical warnings enable pilots to
avoid crashes.
Pilots: Pilots will not fly in planes with collision-avoidance systems that are not fully tested. Malfunctioning
systems could mislead pilots, causing crashes.
The pilots’ objection is most strengthened if which of the following is true?
(A) It is always possible for mechanical devices to malfunction.
(B) Jet engines, although not fully tested when first put into use, have achieved exemplary performance and
safety records.
(C) Although collision-avoidance systems will enable pilots to avoid some crashes, the likely malfunctions of
the not-fully-tested systems will cause even more crashes.
(D) Many airline collisions are caused in part by the exhaustion of overworked pilots.
(E) Collision-avoidance systems, at this stage of development, appear to have worked better in passenger
planes than in cargo planes during experimental flights made over a six-month period.


51. Guitar strings often go “dead”—become less responsive and bright in tone—after a few weeks of intense use.
A researcher whose son is a classical guitarist hypothesized that dirt and oil, rather than changes in the
material properties of the string, were responsible.
Which of the following investigations is most likely to yield significant information that would help to evaluate
the researcher’s hypothesis?
(A) Determining if a metal alloy is used to make the strings used by classical guitarists
(B) Determining whether classical guitarists make their strings go dead faster than do folk guitarists
(C) Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung
on various brands of guitars.
(D) Determining whether a dead string and a new string produce different qualities of sound
(E) Determining whether smearing various substances on new guitar strings causes them to go dead


52. Most consumers do not get much use out of the sports equipment they purchase. For example, seventeen
percent of the adults in the United States own jogging shoes, but only forty-five percent of the owners jog more
than once a year, and only seventeen percent jog more than once a week.
Which of the following, if true, casts most doubt on the claim that most consumers get little use out of the
sports equipment they purchase?
(A) Joggers are most susceptible to sports injuries during the first six months in which they jog.
(B) Joggers often exaggerate the frequency with which they jog in surveys designed to elicit such information.
(C) Many consumers purchase jogging shoes for use in activities other than jogging.
(D) Consumers who take up jogging often purchase an athletic shoe that can be used in other sports.
(E) Joggers who jog more than once a week are often active participants in other sports as well.


53. Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald
River was still reproducing adequately in the river below the dam. Since the dam reduced the annual range of
water temperature in the river below the dam from 50 degrees to 6 degrees, scientists have hypothesized that
sharply rising water temperatures must be involved in signaling the native species to begin the reproductive
cycle.
Which of the following statements, if true, would most strengthen the scientists’ hypothesis?
(A) The native fish species were still able to reproduce only in side streams of the river below the dam where the
annual temperature range remains approximately 50 degrees.
(B) Before the dam was built, the Emerald River annually overflowed its banks, creating backwaters that were
critical breeding areas for the native species of fish.
(C) The lowest recorded temperature of the Emerald River before the dam was built was 34 degrees, whereas
the lowest recorded temperature of the river after the dam was built has been 43 degrees.
(D)Nonnative species of fish, introduced into the Emerald River after the dam was built, have begun competing
with the declining native fish species for food and space.
(E) Five of the fish species native to the Emerald River are not native to any other river in North America.

balapupu

answer：~~~~~~~~~~~~~~~~~~~
49.
The hiker’s reasoning assumes that the number that faced her indicated distance from the path’s beginning. The
numbers on the second milepost show that this assumption was erroneous. They are, however, the numbers
that would be expected if the facing number indicated the distance to the path’s end with the number on the back indicating the distance from the beginning. Thus choice C explains the discrepancy and is the best answer.
The next milepost being reversed (Choice A) cannot be in explanation, because if the hiker’s reasoning were
accurate both numbers on the milepost would be 22. The units (choice B) would not affect whether the number
became smaller or larger. Nor would a missing milepost (choice D) affect the direction of change. The mode of
transportation (choice E) is irrelevant to distance.
50.
Choice C states that what the pilots think could happen is likely to happen. Thus, C is the best choice.
Choice A is inappropriate because it says nothing about the malfunctions that most concern the pilots-those that
might mislead. Nor does A distinguish tested from not-fully-tested systems. Choice B is inappropriate. The only
outcome of using insufficiently tested equipment that might strengthen the pilots’ objection is an unfavorable one,
but B reports on a favorable outcome. Choice D is inappropriate because it mentions a problem that needs to be
addressed whether or not the collision-avoidance systems are installed immediately. Choice E is inappropriate
because it provides no evidence that any malfunctions were of a sort to mislead pilots and cause crashes.
51.
The hypothesis has two parts: first, that intense use does not bring material changes that cause the string to go
dead and, second, that dirt and oil do cause the phenomenon. The experiment suggested in choice E directly
tests this hypothesis by contaminating strings that are known to have their original material properties. Thus, E is
best answer.
Because factors associated with style of play (choice B) and brand of guitar (Choice C) might affect how the
strings become contaminated, no result of the investigations in B and C will allow clear evaluation of the
hypothesis. Information about the strings’ material (choice A) will need considerable supplementation before its
bearing on the hypothesis is clear. The passage already gives the information promised by investigation D.
52.
The claim that most consumers do not get much use out of the sports equipment they purchase is supported by the infrequency with which jogging shoes are used for jogging. This reasoning overlooks the possibility that
jogging shoes are used for other purposes; thus, choice C is the best answer.
Because injured joggers are less likely to use their jogging shoes, choice A is inappropriate. If B is true, joggers
use their jogging shoes even less than the study cited states. So choice B is inappropriate. Because the
consumers and joggers mentioned in D and E respectively are most likely to be among those who frequently use
sports equipment and whose existence the argument concedes, D and E are inappropriate.
53.
For the hypothesis to be tenable it is important that the fish in streams in the Emerald River area that retain a
wide temperature difference have not lost their ability to reproduce. Choice A asserts that these fish could still
reproduce and is thus the best answer.
Choice B undermines the hypothesis by suggesting a completely different hypothesis; choice C tends to support
the claim that the temperature variation has lessened but does not show that this is the right explanation; since
D relates a development after the native species began to decline, it does not bear on the hypothesis, which
concerns the decline’s original cause; and choice E emphasizes the seriousness of the problem but sheds no
light on what causes it.

bananazoo

占位~

fox0923

占位~

-- by 会员 bananazoo (2011/10/29 0:41:37)

bana占位好勤快阿！什么时候我可以坐沙发？