1. I said would eat a carrot for lunch.我说过（之前），我午饭会吃根胡萝卜。
这里would 是 will 过去式变形，构成时态
2. If I were you,I would eat a carrot.如果我是你，我会吃根胡萝卜。
这里would是构成eat的虚拟语气，我不可能成为你，所有这里的吃是虚拟动作。
3. Would you pass me the carrot, please?能请你把胡萝卜递过来吗？
比Will you pass me the carrot, please?更礼貌
4. Would you like a carrot for lunch?你中午想吃根胡萝卜吗？
比Do you want a carrot for lunch?更礼貌
