The contract can be terminated by either party with three months' notice.

合同的任何一方如提前三个月通知，均可终止本合同。

《牛津词典》

The election will decide if either party controls both houses of Congress.

这次选举将决定是否由任一党控制国会两院。

《柯林斯英汉双解大词典》

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It was a party of protest, formed by men who refused to support either of the two old parties.

VOA: special.2010.06.03

If there are additional ideas from either party, I'm happy to consider them, as well.

WHITEHOUSE: Creating Jobs Through New Small Business Initiatives

And by no means are these kinds of actions a monopoly of either party.

FORBES: Brown Whitman Race Begs The Question: What's The Worst Thing That Can Happen?

But in most elections, that exasperation does not hurt or help either party disproportionately.

NPR: What Would It Take To Flip the House?