请问“i think it's favour for you to do that"语法是否有误

有一点错误,应该:
I think it's a favour for your to do that.
虽然没有上下文,但我觉得如果用以下说法会更好:
Please do me a favour to do that.

补充："我认为你那样做对你有利" This is favorable for you ( to do that ).

There is no grammar mistake, however, this sentence does not make any sense~~
The correct way of saying 我认为你那样做对你有利 should be:
I think it is on your behalf to do that.

错了，favour前面必须要加a

favour前加a较好,do sb. a favour