请教版主关于必要充分的问题

1.凡是问

The argument above is based on 或者depends on  which of the following assumptions?

这样的题目都是必要型的吧，如果不是，怎么才能看出一个题目是充分型还是必要型的？

an assumption of the passage is that?  这种问法是充分型的么？

2.怎么看出题目考察的是“除了隐含的假设外没有别的因素影响结论”，是结论对吧

是不得看文中有没有几个事物之间的比较？？

1。你说的当然必要型。充分型是在问题出现这样的话：下列那个假设，能使原文的结论合理推出（黑体部分一定要出现）。正是说原文的结论能合理推出，才有充分型和必要型的区别：充分型的答案加到原文，结论一定能得出，其实这点是来源于问题的要求（结论合理推出）。而必要型假设就不必要结论一定能推出。

2。不明白你的意思。你是说他因吧。

哦，是他因，怎么能看出他因的题型呢，是不得看文中有没有几个事物之间的比较？？

比如下面的

An acre of average farmland produces about 400 pounds of grain amaranth ,as against 2,400 pounds per acre,or six times as much,for wheat.It follows that whenever the grain-amaranth price is projected to be more than six times the projected price of wheat,farmers wishing to maximize profits will grow grain amaranth rather than wheat.

The argument above is based on which of the following assumptions?

答案a An acre's worth of grain amaranth is no more expensive to grow and bring to market than acre's worth of wheat.