It pays to know the enemy — not least because at some time you may have the opportunity to turn him into a friend.

了解敌人对我们还是有好处的- - - - - - -特别是那种有可能在某一天成为你的朋友的人。

youdao

As the Chinese saying goes, "know the enemy and know yourself, and you can fight a hundred battles with no danger of defeat", one should know both himself and his counterpart to win each battle.

中国有一名话：“知己知彼，百战不殆。”意思说，打仗的时候，既要了解自己，还要了解自己的对手，这样才能在每场战役中取胜。

youdao

You know what the real enemy to happiness is?

你知道幸福的真正敌人是什么吗？

youdao

"We know that her husband's political enemy, Mister D'Arcy,stole the letter.

VOA: special.2009.12.26

Socrates seems to dissolve those bonds of familiarity, loyalty and attachment : that we all have by saying to Polemarchus, "How do we know, how do we really know "? the distinction between friend and enemy?"

苏格拉底似乎要解开,那些我们都习以为常的常规，忠诚与情感附属的束缚,所以才向，Polemarchus，提问，“我们如何得知，我们如何真正得知,朋友与敌人间的区别“

耶鲁公开课 - 政治哲学导论课程节选

They know the enemy has options, and they want to deny the enemy those options as much as possible.

NPR: Is the Iraq Surge Strategy Working?

Our armed forces - like their counterparts in the intelligence community, Department of Homeland Security and law enforcement - have a professional duty to know the enemy and develop appropriate responses to the threat doctrine.

CENTERFORSECURITYPOLICY: The real reason they hate us

This was the essential difficulty of the task at hand: The higher-ups in the U.S. Army needed to know about the enemy in this unexplored province, so in order to learn as much as they could, they were going to stick a small group of troops in its midst.

CNN: Excerpt: 'The Outpost: An Untold Story of American Valor'