“采取对抗行动”可以翻译为 "take confrontational actions" 或 "engage in confrontational measures"。
"take confrontational actions" 直接表达了采取具有对抗性质的行为，简洁明了。
"engage in confrontational measures" 则更侧重于描述参与或实施对抗性的手段或策略，语境上可能稍显正式一些。
根据具体语境和表达需要，可以选择其中一个合适的表达。例如：
They decided to take confrontational actions against the unfair policies. （他们决定对不公平的政策采取对抗行动。）
The government warned that it would not hesitate to engage in confrontational measures if necessary. （政府警告说，如有必要，将毫不犹豫地采取对抗性措施。）