1. "You'd better calm down" can be translated into "你最好冷静下来" in Chinese.
2. To express this phrase in a different way, you could say "It's important to remain composed."
3. Another way to translate the phrase is "你需要冷静一下。"
4. The phrase "You'd better calm down" can also be interpreted as "你应当控制一下自己的情绪。"
5. In a more formal context, you might say "It is advisable for you to compose yourself."
