GWD4-Q11

我是小苞

Because ethylene dibromide, a chemical usedto fumigate grain, was blamed for the high rate of nerve damage suffered bypeople who work in grain-processing plants, many such plants switched to otherchemical fumigants two years ago.  Sincethen, however, the percentage of workers at these plants who were newlydiagnosed with nerve damage has not dropped significantly.  Therefore, either ethylene dibromide waswrongly blamed or else the new chemicals also cause nerve damage.

Which of the following is an assumption onwhich the argument depends?

1. If the new chemicals cause nerve damage, the nerve damage     caused would be different from any nerve damage that ethylene dibromide     may cause.
   
2. There are no chemical fumigants that are completely safe for     workers in grain-processing plants.
   
3. If ethylene dibromide causes nerve damage, it does not take two     years or longer for that damage to become detectable.
   
4. Workers at grain-processing plants typically continue to work     there even after being diagnosed with nerve damage.
   
5. Workers at grain-processing plants that still use ethylene     dibromide continue to have a high rate of nerve damage.
   

一直在CD中徘徊，请高人指教，谢谢

coolhaoming

问假设，只要将假设去否，然后看是否削弱题干即可。

C取否后：如果ED导致了神经问题，那么它需要两年或者更长的时间才能检测出来。这就说明了结论是错误的。既不是被错误的指责了，又不是其它物质导致的。而是ED导致的，只不过现在导致的问题是两年甚至更早之前就留下原因的。削弱了题干

D取否后：在被诊断出神经问题后，工人不再在这里工作了。既然不在这里工作了，那么持续的神经问题病人说明什么呢？只能是其它化学物质导致，加强了题干，所以D不对。

dec0412