正文：
What for?
到底要干吗?
What's the point of making so much trouble?
费那么大力气有什么用呢？
I don't hold with the idea to leave him alone.

我不赞成不管他。

经典句扩展：
I am really displeased about your imprudence.
我不赞成你的轻率行为。
I can't favor your plan.

我不能赞成你的计划。
Is that really necessary?

真的有必要吗？
Is it really necessary to lose temper?

发脾气真的有必要吗？
It's not a correct thing to do actually.

这样做是不对的。