Be helpful 后面加什么介词

Be helpful 后面加什么介词？

后面加介词to，例如：

1.The following information may be helpful to readers.下列信息可能对读者有用。

2.Lionel asked me how things were going at work, but I suspect he was just fishing for information that might be helpful to his own company.莱昂内尔问我工作情况如何，不过我怀疑他只是想探听一些可能对自己公司有帮助的消息。

3.The booklet should be very helpful to parents of disabled children.这本小册子对于残疾儿童的父母会很有用。

Be helpful 后面常加介词in，表示在某方面有帮助，接介词to，表示对某人有帮助，也可以接for sb to do.

加to，，，，，，，，