Translation of "Helpful" in Chinese

- Can I help you?
- Can I be helpful?
- Can I be helpful to you?

我能幫你嗎？

Your comments were always very helpful to me.

你的意見總是對我有幫助。

He may be clever, but he is not very helpful.

他很聰明，但卻不太幫得上忙。

It would be helpful if you could do that for me.

您那样做的话，可就帮到我了。

- It would be much appreciated if you would do that for me.
- I'd appreciate it if you did that for me.
- It would be helpful if you could do that for me.

您那样做的话，可就帮到我了。