She could not give us a _______ explanation for her decision to

She could not give us a _______ explanation for her decision to give up the opportunity.（reason）
【正确答案】：reasonable
【题目解析】：译文：她不能给我们一个合理的解释，解释她为什么放弃这次机会。根据译文可知，空缺处应填形容词，表示“合理的”意思，所以应填reasonable。答案为reasonable。