They believe they're playing a zero-sum game, where both must compete for the same resources.

他们认为他们在玩一场零和游戏，双方必须争夺同样的资源。

《柯林斯英汉双解大词典》

Both must rely on superdelegates.

双方都要依靠超级代表的支持。

youdao

Both must be clearly defined and drawn up.

两者都必须清楚地加以定义并拟定出来。

youdao

The United States Senate and Russia's parliament must both approve the agreement for it to take effect.

VOA: special.2010.04.17

Both the House and the Senate must approve a bill in order for it to become law.

VOA: special.2009.08.14

General MacArthur told the Japanese they must change, both politically and socially.

VOA: special.2009.05.24

Now both must also contend with McDonald's entry into the frozen and specialty coffee market.

FORBES: The Way We'll Be

Both must report the fair market value of goods or services received on their tax returns.

FORBES: Trades And Swaps? IRS Gets A Piece (Really)

We both must try to understand complicated systems with intricate feedbacks and uncertain causality.

FORBES: Can We Really Call Climate Science A Science?