名人教英文：at / to the... of someone
at the... of someone 和 to the... of someone 都是英文常见的词组结构。at the... of someone 或 at someone's... 本身没有特定意思，整个词组的意思取决于配什么字。以下是一些较常见的例子。
at the expense of someone/something，意谓「以（损害/牺牲）……为代价」，如：
in the face of the debt crisis, many european countries have to cut budgets at the expense of social welfare programs.
at the mercy of somebody/something 即「受……摆布」，如：japan's earthquake in 2011 showed that all human beings, whether rich or poor, are at the mercy of mother nature.
at someone's discretion 即「由……决定」，如：the thief's sentence is at the discretion of the court.
at someone's disposal 即「可供……使用」。如：with limited resources at their disposal, small and medium-sized enterprises often find it difficult to raise their productivity.
at someone's command 的意思是掌握某种技能或资源，能够运用自如。常见的写法为 have/with something at someone's command。如：he has a rich english vocabulary at his command.
at someone's request /invitation 即「应……的要求/邀请」。如：
?the meeting was arranged at the manager's request.
?south korean president park geun-hye will visit the united states at the invitation of president barack obama.