Nobody really likes them, but they are a necessary evil.

没有人真正喜欢它们，但它们是必要之恶。

youdao

Some may think that Musharraf’s scheme to stay enthroned is a necessary evil in the service of a greater good. That’s half right: It is evil, but it’s not necessary.

有些人认为穆沙拉夫继续独揽大权的计划是成大善难免小恶，这只说对了一半，这是恶，但不是“难免”。

youdao

Appraisals no longer need to be viewed as a necessary evil but rather as a tool that can be used to enhance your career.

评估不是“必要的罪恶”，相反那是提升自己职业生涯的工具。

youdao

Such stories are embarrassing, Mr Rasmussen says, but a necessary evil.

BBC: Lars Rasmussen: the brains behind Facebook's future

Yes, massive industry events are often better at sorting companies with and without stellar marketing budgets than the wheat from the chaff, so to speak, but it's also a necessary evil.

ENGADGET: E3: RIP? Like, for reals?

But her admirers believe the pain was a necessary evil to save this nation from an even greater catastrophe: in hastening the end of mining and other "rust bucket" industries, they argue, she managed to make us leaner and fitter, faster.

BBC: The 'Thatcher Factor': My personal post script