helpful用作形容词，有给予帮助的，有益的，愿意帮忙，(事物）有助于改善局面的，有好处的等含义。

1.用作形容词

Having the right equipment at hand will be enormously helpful.

手头上有合适的设备将会帮上大忙。

An A to Z of careers gives helpful information about courses.

按字母顺序排列的职业大全提供了有助于课程选择的信息。

During the war his pacifist leanings were not helpful.

战时他的和平主义思想派不上用场。

2.be helpful in doing sth. 对做某事有帮助

We hope this leaflet has been helpful in answering your questions.

我们希望这个宣传单可以帮助您找到您想要的答案。

3.it is helpful (for sb) to do sth

It is helpful to discuss your problems with your friends.

跟你的朋友们聊聊你遇到的问题是有好处的。这里的It是形式主语，真正的主语是to后面的句子

4.be helpful for sb对某人事有益的

Music with the sounds of the ocean or bird song can be helpful for some.

大海的声音或者鸟叫声对你的睡眠时很有帮助的。