紧要的英文：
moment

Make a difference; cause a difference
紧要;关系重大

Once a satisfactory system of lubrication has been secured the hardness of the interacting elements becomes critical.
一旦获得了满意的润滑系统，相互作用的元件的硬度就成为紧要之事。

The inmost,choicest,or essential part;the pith.
实质，精华，精髓最深层、最紧要或最必要的部分;精华

She ignores the vital question of pace.
她忽略了最紧要的速度问题。

We have omitted footnotes which we judged inessential to the text.
我们略掉了我们认为对正文不甚紧要的脚注。

I've got a lot of urgent work to do at home and will have to go into purdah for a couple of weeks.
我有许多紧要的工作须在家里做,因此要有几个星期足不出户.

"True, there are many girls in your honourable province. Only those of the first grade are registered here."
"贵省女子固多,不过择其紧要者录之"

Editors of newspapers and magazines Often go to extremes to provide their readers with unimportant facts and statistics.
报刊杂志的编辑常常为了向读者提供成立一些无关紧紧要的事实和统计数字而走向极端。

at this exigent moment
在此危急关头

On the spur of the moment
一时冲动

stalling moment
失速力矩|使气流离体力矩

He relaxed for a moment.
他浑身放松了一会。

At the very moment, there was a loud crack.
就在那一刹那，突然传来一阵巨大的爆裂声。