请教：将原文的意思换个说法算不算正确的assumption？谢谢

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?

1. People in western Africa did not develop staple crops that they stopped cultivating once rice and yams were introduced.

2. There are no plants native to western Africa that, if domesticated, could serve as staple food crops.

3. Rice and yams were grown as staple crops by the earliest agricultural societies outside of western Africa.

4. Kola and okra are better suited to growing conditions in western Africa than domesticated rice and yams are.

5. Kola and okra were domesticated in western Africa before rice and yams were introduced there.

   答案是a，可是我觉得它只是把原文重说了一遍。记得在做feifei的时候他说将原文意思复述不算，那位牛人给解释一下好吗？谢谢！

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.

可是文章中已经说明all the recorded staple crops beginning with r&y了呀！是不是和这个recorded 有关呢？用A来确定record是正确的？

可是文章中已经说明all the recorded staple crops beginning with r&y了呀！是不是和这个recorded 有关呢？用A来确定record是正确的？

在考古题中,以前的假设是可以被不断推翻的.

OG182是个差不多的题

all the recorded staple crops

and

all the staple crops

Two items listed above are not the same and "all the staple crops" contains"all the recorded staple crps".So choice A doesn't talk about the same thing as that listed in the argument.Unfortunately ,the recorded staple crop is the basis on which argument draw its conlusion.And choice A eliminated a situation that would wekan the conclusion.That is to make sure that "all the recorded staple crops" is the same thing as "all staple crops".

hence ,choice A is the correct answer ,whose patten is "not + weaken"

incisive! totally consent with U.