necessary需要的,必需的
We must not put them in more danger than is needful.我们一定不能让他们处于不必要的危险中。
needing something需要…的
They are needful of affection.他们需要关爱。
do the needful UK old-fashioned or Indian English to do what is necessary in a situation做必需做的事
Notify your bank and they will do the needful.通知你的银行,他们会处理该办的手续。