Higher taxes may be a necessary evil.

提高税率虽不是件令人愉快的事，但可能是必要的。

《柯林斯英汉双解大词典》

Meanwhile, government spending that would make everyone better off was being cut down because people instinctively—and wrongly—labeled government only as "a necessary evil".

与此同时，本可以让每个人生活更好的政府开支却被削减了，因为人们本能地——且错误地——将政府贴上了“必定邪恶”的标签。

youdao

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

They believed that it was a necessary evil.

VOA: special.2011.04.07

Some would get worried and they would discuss slavery as a necessary evil this system entailed upon them.

有些人感到忧虑,他们认为传承下来的奴隶制,毫无疑问是种罪恶

耶鲁公开课 - 美国内战与重建课程节选

Pylons are a necessary evil if we are to wean ourselves off carbon-based energy.

BBC: Landscape impact of electric pylon softened by design?

Mr Balkwell's father Les told BBC News the exhumation at Upminster Cemetery was "a necessary evil".

BBC: Exhumation of Lee Balkwell in concrete mixer death probe

Free-market advocates, such as The Economist, then become mere apologists for it as a necessary evil.

ECONOMIST: Capitalism's future