GMAT逻辑题练习及答案(466)

2017-12-08 11:32

来源：新东方在线

作者：

　　Theonly physical factor preventing a human journey to Mars has been weight.Carrying enough fuel to propel a conventional spacecraft to Mars and back wouldmake even the lightest craft too heavy to be launched from Earth. A device hasrecently been invented, however, that allows an otherwise conventionalspacecraft to refill the craft’s fuel tanks with fuel manufactured from theMartian atmosphere for the return trip. Therefore, it is possible for people togo to Mars in a spacecraft that carries this device and then return.

　　Which one of the following is an assumptionon which the argument depends?

　　A. Theamount of fuel needed for a spacecraft to return from Mars is the same as theamount of fuel needed to travel from Earth to Mars.

　　B. Thefuel manufactured from the Martian atmosphere would not differ in compositionfrom the fuel used to travel to Mars.

　　C. Thedevice for manufacturing fuel from the Martian atmosphere would not take up anyof the spaceship crew’s living space.

　　D. Aconventional spacecraft equipped with the device would not be appreciably moreexpensive to construct than current spacecraft typically are.

　　E. Thedevice for manufacturing fuel for the return to Earth weighs less than thetanks of fuel that a conventional spacecraft would otherwise need to carry fromEarth for the return trip.

　　答案

　　The correct answer is (E)

　　See: Assumption question

　　Think: I have to find the conclusion, thenthe evidence, and from them figure out the central assumption.

　　Do:

　　Conclusion: The “what” of an argument

　　In this case:

　　Itis possible for people to go to Mars in a spacecraft that carries this deviceand then return.

　　Evidence: The “Why” of an argument

　　In this case:

　　E1:

　　The only physical factor preventing a humanjourney to Mars has been weight. Carrying enough fuel to propel a conventionalspacecraft to Mars and back would make even the lightest craft too heavy to belaunched from Earth.

　　E2:

　　A device has recently been invented,however, that allows an otherwise conventional spacecraft to refill the craft’sfuel tanks with fuel manufactured from the Martian atmosphere for the returntrip

　　Assumption: Facts or ideas, not stated in the passage. The assumption must be trueif the argument is to be considered valid. The assumption typical directly links theevidence with the conclusion. The best way to tackle it is to negate it.

　　In this case:

　　The device for manufacturing fuel for thereturn to Earth weighs less than the tanks of fuel that a conventional spacecraftwould otherwise need to carry from Earth for the return trip.

　　If we negate the assumption, the conclusioncan’t come to pass.

　　The device for manufacturing fuel for thereturn to Earth weighs more than the tanks of fuel that a conventional spacecraftwould otherwise need to carry from Earthfor the return trip, then the conclusion can’t come to pass in new inventeddevice term.

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