语音讲解：
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　　定义：

　　at the point ofshavingsexhausted one's last idea or mental resource

　　已耗尽某人的思想或精神来源

　　例句：

　　She had been at her wit's end trying to think up an idea for her composition assignment.

　　她为了作文作业苦思冥想,已到了江郎才尽的地步。