I don't think you should mention it at the beginning of the story, or it may ____ the shocking ending.  [ ]

A. give out      

B. give away    

C. give up      

D. give off

太阳活动对地球造成的影响有（）①引起潮汐现象②干扰无线电短波通讯③产生“磁暴”现象④诱发降水量变化

A.①②③

B.①②④

C.②③④

D.①③④