During the debate, he had to think on his feet to counter his opponent's arguments. 【误译】在辩论中，他不得不在脚上思考来反驳对手的论点。 【正确】在辩论中，他不得不随机应变来反驳对手的论点。 说明： think on one's feet 并非指真的“在脚上思考”。它是一个习语，意为“反应敏捷”、“随机应变”或“临场发挥”。