补充18 ， 16

麻集爱

16. After observing the Earth’s weather patterns and the

   11-year sunspot cycle of the Sun for 36 years, scien-

   tists have found that high levels of sunspot activity

   precede shifts in wind patterns that affect the Earth’s

   weather. One can conclude that meteorologists will

   be able to improve their weather forecasts based on

   this information.

   Which of the following, if true, most seriously

   weakens the argument above?

   (A) Weather forecasts are more detailed today than

       they were 36 years ago.

   (B) Scientists can establish that sunspot activity

       directly affects the Earth’s weather.

   (C) Evidence other than sunspot activity has previ-

       ously enabled meteorologists to forecast the

       weather conditions that are predictable on the

       basis of sunspot activity.

   (D) Scientists have not determined why the sunspot

       activity on the Sun follows an 11-year cycle.

   (E) It has been established that predictable wind

       patterns yield predictable weather patterns.

答案为c ， 我无法理解c如何削弱了结论， 我最后五个选项都没选，~~衰~~

mindfree

I think the key is understanding. Argument says that sunspot activities will help predict weather. C points out that something other than sunspot has already provided such information equivalent to what sunspot activities can provide. It means that sunspot activities will not provide new information.

perpetual

总教头说话就是有水平哦~~~~

麻集爱

非常感谢～