help的形容詞的最高級是？

　　例句：

　　The booklet should be very helpful to parents of disabled children.

　　這本小冊子對于殘疾兒童的父母會很有用。

　　Role-play is helpful in developing communication skills.

　　角色扮演有助于提高溝通技巧。

　　Sorry I can't be more helpful.

　　對不起，我幫不上更多的'忙。

　　You'll find her very helpful ─ if she's not too busy, that is.

　　你會覺得她很肯幫忙，那是說如果她不太忙的話。

　　She was very helpful when my mother was ill ─ I'll allow you that.

　　我母親生病時她幫了很大的忙——我同意你說的這一點。