It describes the peak state where your mind is completely engaged with a task.

意思就是说你脑海被一件事完全地占据。

youdao

I can certainly get used to this peak state becoming the everyday norm. Now I feel it would be a big sacrifice to go back to monophasic sleep.

当我习惯了这种感觉之后，我相信我肯定不会很愿意回到单相睡眠的状态。

youdao

No state enjoys peak season in September, October, November, or December.

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Also up there is the fallout from a global economic collapse, possibly resulting from a state of peak oil -- the point where oil production reaches its peak and thereafter goes into freefall.

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During the peak of the influenza season, the state of New York had to take the extraordinary measure of declaring a state health emergency in order to activate laws allowing pharmacists to vaccinate children against influenza.

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