百思不得其解阿

yvonnezenith

"If the forest continues to disappear at its present pace, the koala will approach extinction,",said the biologist.
" So all that is needed to save the koala is to stop deforestation,"said the politician.

which one of the following statement is consistent with the biologists claim but not with the politician's claim?

a. Deforestation continues and the koala becomes exctinct.
b. Deforestation is stopped and the koala becomes extinct.
c. Reforestation is slowed and the koala survivies.
d. Deforestation is slowed and the koala survivies.
e. Deforestation is slowed and the koala approaches extinction.

百思不得其解。答案是b。想不出个所以然，一开始觉得挺简单的，却绕不出来了。
[em03]

[此贴子已经被作者于2003-5-23 16:20:44编辑过]

StephanieYun

典型的命题式逻辑， 想想命题,原命题,逆否命题










生活是一杯清茶

yvonnezenith

是，应该有一类的题目是这种思维。
a是原命题，d是逆否？c不对，剩下e和b什么区别？怎么看出符合一个，不符合另一个？
望赐教，实在晕。

StephanieYun

对小b的原名题取逆否命题，你得到什么呢？

看看小P的命题是什么，

再看看题目问什么呢？------ 要找一个答案， 他要只可以符合小b， 不能符合小p ; 前者，符合小b就是符合小b的原名题和它的逆否命题，后者， 不能符合小p就是说停止去森林化并不能使可爱的小考拉koala摆脱灭亡的命运，“" so all that is needed to save the koala is to stop deforestation,"said the politician.”

再看看选项给了我们什么可爱的选择呢？


现在，懂了吗？















生活是一杯清茶

yvonnezenith

清茶妹妹，
多谢。