单选题 What does the author say about the weather?

A、 It is rare for Washington,D.C. to have such long rainy days.
B、 It has been mining since Sept 26^th for the most of the time.
C、 It is favorable to the manufacturers to promote solar equipment.
D、 It has helped see the disadvantages of solar energy.

【正确答案】 D

【答案解析】由the conditions may have made for a more revealing demonstration of solar energy than was originally planned可知这种天气可能会使太阳能的利用比所预计的更暴露一些缺点。所以D(有助于看到太阳能的弊端)是正确答案。