If something is very important more than anything else then it is said to be the 'most importan' thing or 'priority'
the key to something is the key point and important
何かが他の何よりも重要なら、それは 'most important'（最も重要）や 'priority'（優先事項）が使えます。
'the key' は「鍵となる重要なこと」を表します。
Being efficient and productive at work is a requirement.
You must work quickly because it is the most important thing at work.
It's best to accomplish work tasks quickly.
Being efficient and productive at work is a requirement.
You must work quickly because it is the most important thing at work.
Speed is very important at this job.
You must learn to do your tasks quickly since it is a priority.
It's best to accomplish work tasks quickly.
（仕事は素早く終わらせるに越したことはありません）
Being efficient and productive at work is a requirement.
（手際が良く生産性が高いことは必要条件です）
You must work quickly because it is the most important thing at work.
（手際良く作業をすることが最も重要です）
Speed is very important at this job.
（この仕事ではスピードが重要）
You must learn to do your tasks quickly since it is a priority.
（手際良く作業ができるようにならなければなりません。ここではそれが優先されます）
スピードが命！というのは、比ゆ的な表現になっていますね。命というのをより具体的な表現にしてあげることで、ふさわしい英語の表現が見つかると思います。ここでは、命＝優先事項として英語に直しました。この表現は、Safety is our priority（安全第一です）と飛行機の機内アナウンスで聞いたりもします。
If you want to say that speed is important, then you may like one of the above suggestions. As completing something within a certain time means that, your speed of output is important, you could equally stress that the time element is important as it is limited. The first suggestion is a well-known phrase in the UK.
"Speed is key"
For something to be 'key', in this context, is implying that 'speed' is the top priority, should be the thing you must be most concerned about.
"Speed is at the top of our list"
The 'top of our list' is another expression used for something that is a top priority, something that is at the up most importance.
"Speed is key"（スピードが鍵です）
'key' はここでは、スピードが「最優先（最も重要なこと）」であることを表します。
"Speed is at the top of our list"（スピードが最優先です）
'top of our list' も、「最優先のもの、最も重要なこと」を表します。
Productivity levels are measured by how fast or how efficient work can be completed.
It is necessary to have good pace when working as this will allow for great results.
We can use the above expressions to describe that speed is important in a work environment.
Productivity: levels of production, what gets done.
Efficient: being highly capable.
Priority: what matters most, what comes first.
Speed is everything. はとてもとてもよく使う表現で、こういったシーンにぴったりです。In business は仕事（ビジネス）で、ということを表現したい場合はつけましょう。ただ職場でこれを言ったら当然仕事ではという暗黙の了解があるのでつけなくとも意味は伝わります。
二番目のフレーズは代替案としてほかに何があるかなぁ…と考えてから出したものです。意味はしっかり通じますが、フレーズの「スピード感」はSpeed is everythingの方が圧倒的にありますね。
I am new here, and, everything seems so fast.
I know, I was like that when I first started.
But why is everything so fast?
Well, speed is the priority.
I hope that helps.
Have a great day.
Will
Here is an example of a dialogue: In this job we have to pump out a lot of units every week, so the pace of the job is very quick, we have to work quickly and accurately, speed is the most important factor however in order for us to continue to hit our production targets. Okay, that makes sense.
We can either use the, "priority," and, "key," to describe this but what is most important the usage of the article, "the," as this in a way describes it being, "the most important." Definite articles help define that you are talking about one specific thing, which in this context as to do with the biggest goal or, "priority."
When saying that you need to work fast. Being productive but being quick at it is being efficient.
Examples;
- In this line of work, speed is key.
- Try to work as fast and efficiently as possible.
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