helpful to還是for

helpful to 和 heplful for 都有"有助於"的意思，但 helpful to 較常用於接sb，而 helpful for也可以接sb，但多用於接sth或doing sth，表示"對....有益"。

例： Swimming is helpful for bones that are porous and weak.
游泳有助於改善骨質疏鬆和骨骼脆弱。
This system has been experimented in practical business work, it is helpful for promoting working efficiency.
本系統已在實際業務工作中投入使用，有助於提高工作效率。
he assertiveness training is very helpful for improving one's social skill.
自信訓練對提高社交技巧很有幫助。

helpful for sb 的情況(sb一般是第一/二/三人稱的主格或賓格)：
1、I think it's helpful for me to learn English well.
我認為它有助於我把英語學得更好。
2、Don't throw it, it is helpful for us to repair the bike.
別扔了它，它對我們修自行車有幫助。
3、I hope the two wise scholars'ideas on learning can be helpful for you.
我希望，這兩位智者的思想可以在學習上對你們有所幫助。

help to sb的指向性較強，強調幫助的對向性，“什麼”對“什麼人”是“有用的、有幫助的、有益處的”。
例：The following information may be helpful to readers.
下列資訊可能對讀者有用。
This is written about me on the diagonal recurrent neural network procedures, may be helpful to you.
這是我寫的關於對角遞迴神經網路的程式，或許對你有所幫助。
But many believe that informal channels and conversations in the work place can be helpful to employers.
但許多人認為，在工作場所的非正式溝通渠道和交談可能對僱主們有益。
The principles should be helpful to the designer of a new engine system.
這些原則要有助於新發動機系統的設計人。