【正确答案】 A

【答案解析】[解析] 这些就是他们做这件事的动机。句中motives：动机。reasons：原因，如：I don't fully understand his reasons for leaving．我不完全理解他离开的理由。excuses：借口，如：His excuse for being late was that he had missed the train．他迟到的理由是没有赶上火车。answers：答案，如：I'm waiting for an answer to my letter．我正在等候回信。plans：计划，如：Do you agree to my plan?你同意我的计划吗?只有reasons意思上和motives最接近。