你好

应该用of

it is good of you to help me.  非常感谢你对我的帮助.

it is good for you to help me. 帮助我对你是有好处的.（很明显不符）

保证准确率~

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祝你学习进步,更上一层楼!

不明白请及时追问,满意敬请采纳,O(∩_∩)O谢谢~~