英语选词填空 SATThey were not ____ misfortune,having endured more

英语选词填空 SAT
They were not ____ misfortune,having endured more than their share of _____.
A.cognizant of .calamity
B.superstitious about...prosperity
C.jealous of ...success
D.oblivious to...happiness
E.unacquainted with...adversity
正确答案是E,但不太明白：E的话,他们对misfortune不陌生,因为他们经历过比their share of adversity更多的...句子中的"their share of adversity"是指他们共同经历的逆境吗,如果是这样那整个句子的逻辑是什么?求详细句子翻译及逻辑关系的解释,