### 定义

"Cross the line" 是一个英语短语，通常用来表示某人或某事突破了预设的界限、规则或道德标准，进入了不应进入的领域。这个短语具有强烈的负面含义，暗示着行为的不当或越界。

### 用法

1. **作为动词短语**：When someone or something crosses the line, they go beyond what is considered acceptable or proper.

   - Example: "He kept making inappropriate comments, and finally, he crossed the line when he made a sexual advance."

   - Translation: "他不断地发表不适当评论，最后当他提出性暗示时，他已经越界了。"

2. **在比喻意义上**：This phrase can also be used metaphorically to describe exceeding a limit in a non-physical sense.

   - Example: "The company's new policy on overtime crossed the line by requiring employees to work on weekends without extra pay."

   - Translation: "公司的新加班政策已经越界，它要求员工在周末工作而没有额外报酬。"

3. **在冲突或争论中**："Cross the line" can indicate a point where a disagreement becomes more intense or personal.

   - Example: "In the debate, she accused him of being dishonest, which really crossed the line."

   - Translation: "在辩论中，她指责他不诚实，这真的触碰了他的底线。"

### 同义词辨析

1. **Overstep the mark**: 这个短语也有类似的意思，表示超过了某个界限或标准。

   - Example: "She overstepped the mark when she publicly criticized her boss's decision."

   - Translation: "当她公开批评老板的决定时，她越过了底线。"

2. **Go too far**: 这个表达强调行为的过度，通常用于描述行为的不适当或过分。

   - Example: "His jokes were funny at first, but they started to go too far when they became offensive."

   - Translation: "他的笑话起初很有趣，但当它们变得冒犯人时，就太过分了。"

3. **Step out of bounds**: 在体育比赛中，"out of bounds" 指出了界，引申为行为超出接受范围。

   - Example: "Their marketing campaign stepped out of bounds by using false advertising."

   - Translation: "他们的营销活动通过虚假广告越界了。"

4. **Transgress**: 这个词更正式，常用于法律或道德上的违反。

   - Example: "The politician was accused of transgressing ethical boundaries."

   - Translation: "这位政治家被指控违反了道德界限。"