help的形容词副词是？

Is he really helpful?

他真的有用吗？

I'm helpful at home.

我在家很有用。

I'm helpful.

我是有用的。

Let me explain!' he added helpfully.

“让我来说明一下！”他热心地补充道。

He gave his name and then helpfully spelled it.

他说出了他的'名字，然后又热心地把它拼读了出来。

She helpfully suggested that I try the local library.

她很热心地建议我试试本地的图书馆。