We'd better take umbrellas—I'm sure it____when we arrive in London; it's always wet there at this time of year.
A.will rain
B.is raining
C.will be raining
D.would rain
答案:C
题目分析:考查将来进行时。A一般将来时;B现在进行时;C将来进行时;D过去将来时。时态题的解题关键是看时间状语或动词的时态。根据时间状语“when we arrive in London(当我们到达伦敦时)”可知是将来某一时刻,将来某一时刻发生的动作要用将来进行时,故选C。