Why did you need a room unless you were up to something?

除非你要捣什么鬼，不然为什么需要一个房间呢？

《柯林斯英汉双解大词典》

I'm leading up to something quite important.

我正要说到很重要的事情上。

《柯林斯英汉双解大词典》

He's up to something or other.

他在做某种事。

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Something was needed to raise up the spirits of the South to break the pressure of Union armies.

VOA: special.2009.10.22

In other words, Foucault is up to something interesting, and probably we should meet him at least halfway to see, to measure, the degree of interest we may have in it.

换言之，福柯在从事很有趣的事业，或许我们至少可以在半途加入他的行列,去看看我们是否也能对此有兴趣。

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so I don't know, I think it's just really cool to be able to work something from the ground up.

所以，我不知道，我就是觉得能从头开始做一件事很酷。

什么是认知科学？ - SpeakingMax英语口语达人

These nine pieces add up to something considerable, and form a vital addition to the corpus.

NEWYORKER: Laureate of Terror

Was Mr. Cornelius just absent minded in not recording the deed or was he up to something ?

FORBES: Sale Of Hartford Property For Delinquent Real Estate Taxes Whets Appetite For Rest Of The Story

The concertina and armed patrols suggest that Bigelow is up to something unusual, something expensively unusual and quite sensitive.

FORBES: Magazine Article