Finally, I got the point of you. 没有浪费sdar的苦口婆心!感谢! 通俗一点说就是:文中的结论是先存在的,承认它的正确性。然后在选项里找:If NOT necessary condition, then NOT conclusion. 这也就是为什么“取非削弱”了! The price of TV assembled in B has increased. This statement is wrong. A price increase in TV assembled in B is not necessary for the conclusion -TV imports from V to B has increased- to hold. 请问:能否举例什么除了asemble hour decreased in B外,什么样的选项,或者结论的必要条件也可以成为正确选项呢?
最后一个小问题:what is LR bible? I am thinking about reading Manhattan CR. Does it help?
There are conditions which are both necessary and sufficient in an argument (if and only if A, then B). However, that does not mean EVERY necessary condition is sufficient.
Back to your example:
这人是女的 不能推出 生孩子 This means, 这人是女的 不是 生孩子 的充分条件 She could have certain disease which prevents her from bearing a child. So in your example, 这人是女的 不是 生孩子 的必要条件也是充分条件
If and only if medusa posts a question, sdcar sneezes. In this example, "medusa posts a question" is the sufficient and necessary condition for "sdcar sneezes."