狒狒70

70. A low-pressure weather system is approaching Plainville; rainfall results from about 70 percent of such systems in the Plainville area. Moreover, the current season, spring, is the time of year in which thundershowers, which sometimes result from low-pressure systems, are most likely to occur in Plainville.

Knowing which one of the following, in addition to the information above, would be most useful for determine the probability that Plainville will have a thundershower soon?

A.        the percentage of thundershowers in Plainville that occur in the spring

B.        the percentage of spring rainfalls in Plainville that are thundershowers

C.        the percentage of thundershowers in Plainville that result from low-pressure systems

D.       whether low-pressure systems in other areas are associated with rainfall

E.        whether Plainville has more or fewer thundershowers each spring than do near by towns

答案到底是B还是C啊？

C。

知道 percentage of thundershowers in Plainville that result from low-pressure systems ，再乘70%（低压天气导致降雨 的概率），就可知下雷阵雨的概率。

楼上的楼上的小姐姐提出的理论似乎更支持b吧

我同意选b