某人做某事是必要的。

It's necessary for sb. to do sth.

youdao

做某事是没必要的。

There is no need for you to go.

youdao

对某人来说，做某事没有必要。固定句型。

There is no need for sb. to do sth.

youdao

or, to express the need for somebody else to either do something or have something.

也可以表达其他人做某事的必要或对某物的需求。

I need 课堂 - SpeakingMax英语口语达人

In another situation, you can use the "I need" pattern to express what somebody else needs to do.

在另一种语境中，你也可以用“I need”句型来表达其他人做某事的必要。

I need 课堂 - SpeakingMax英语口语达人