You need to pay attention to the main conlcusion: Space flights carrying astronauts must continue. The premises supporting this conclusion are: 1) Space flights with astronauts are needed to repair satellites 2) Without repairs, the satellites would eventually malfunction The assumption is that we NEED these satellite to function. E) points out that we do not need these old satellites anymore since new ones are cheaper and better. C) on the other hand only make the spaceflight difficult to make without REMOVING the root cause to make such flights. For example, the statement "I must eat this drug to fight cancer." If the drug's price is doubled, would your statement weakened? No. You still need to eat the drug to survive, although you might die from bankcrupcy instead of cancer. But if there is a new, cheaper, alternative treatment, then sure, you do not need to eat the old drug anymore. Thus, the availability of an alternative would weaken the strength of the original statement. -- by 会员 sdcar2010 (2011/6/28 20:24:40)
Thanks for your answer. I get most part and certainly agree with you. Thanks a lot But I still have question based on Manhattan CR, which is "for weaken problem, the answer does not necessary to be the opposite of the conclusion, it may make the conclusion less likely to be valid."
I think C may make the conclusion less likely to be valid, therefore, I cannot really say it's a wrong choice. Could you please help me with this part.
By the way, I mark your thread and am reading it now and feel like the radiant light casting the sky. Thanks again. |