Excuses relieve tension by helping ______ both sides that the mistake was an aberration that will not be repeated.
 
【正确答案】 D
【答案解析】 assure sb that使某人对某事物确信不疑或觉得肯定无误。insure保险,投保。ensure确保,保证。reassure消除某人的恐惧或疑虑,使某人放心。