og 10th 80 根据《逻辑基础知识》解题

Questions 80-81 are based on the following.

The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

80.

The argument in the passage depends on which of the following assumptions?

(A) The supply of illegal drugs dropped substantially in 1987.

(B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.

(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.

(D) The wholesale price of a few illegal drugs increased substantially in 1987.

(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.

80.

The only choice that must be true in order to conclude legitimately from the drop in the wholesale price of illegal drugs that the program was a failure is choice E, the best answer. If the drop in price was caused by a drop in demand, there is no reason to suspect that there has been any increase in supply caused by drugs entering the country.

The other choices can be false without affecting the argument. The supply of illegal drugs need not have dropped (choice A), and the retail price could have dropped (choice B). The entry of illegal drugs could have risen at a higher rate than domestic production (choice C), and no illegal drug need have undergone a substantial price rise (choice D).

如果the program 失败了（p），那么批发价下降（q）（如果the program没有失败，那么批发价不会下降）

根据上述，可见我们只需找出p真q真 /p假q真/ p假q假 中的任何一种情况就可以找出题目假设了，从而使这个判断成立，只有E满足了p假q真/ p假q假这两种情况（因为题目说A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.也就表明了p这个充分条件有可能为“真”---除了a drop in demand 这个原因以外，另外的原因就是题目说的program fail，或者为“假”---另外的原因有可能是其他的而不是program fail）所以（E）提供了假设，使这个判断成立。

问一下LZ，哪里能搞到这个《逻辑基础知识》啊？谢谢！