GWD-9-Q40求问

sarah9142

GWD-9-Q40:
Agricultural societies cannot exist without staple crops. Several food plants, such as kola and okra, are known to have been domesticated in western Africa, but they are all supplemental, not staple, foods. All the recorded staple crops grown in western Africa were introduced from elsewhere, beginning, at some unknown date, with rice and yams. Therefore, discovering when rice and yams were introduced into western Africa would establish the earliest date at which agricultural societies could have arisen there.

Which of the following is an assumption on which the argument depends?

A.    eople in western Africa did not develop staple crops that they stopped cultivating once rice and yams were introduced.
B.    There are no plants native to western Africa that, if domesticated, could serve as staple food crops.
C.    Rice and yams were grown as staple crops by the earliest agricultural societies outside of western Africa.
D.    Kola and okra are better suited to growing conditions in western Africa than domesticated rice and yams are.
E.    Kola and okra were domesticated in western Africa before rice and yams were introduced there.

对A选项的理解感觉不大确定，觉得并没有assume原文，求NN解答~~~

wuxiaodlmu

http://forum.chasedream.com/GMAT_CR/thread-695340-1-1.html?SearchText=gwd%209%2040

可以参考这个讨论

sarah9142

谢谢楼上

sarah9142

但是楼上， 我觉得我还是不能理解他的解释。。。A选项的翻译却是很纠结啊。。我也是选择B的·~~