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Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
the key is
Grammar usage guide and real-world examplesUSAGE SUMMARY
The part of a sentence "the key is" is correct and usable in written English.
You can use it when introducing a solution or piece of advice. For example: "The key is to remain positive no matter what life throws at you."
✓ Grammatically correct
News & Media
Wiki
Formal & Business
Alternative expressions(20)
here
the crucial point is
the critical factor is
the crux of the matter is
it all lies
it all constitutes
the solution lies
the root cause is
it all ties
the key explains
it all sits
the essential element is
it all represents
it all exists
the answer resides in
the bottom line is
the heart of the matter is
it all illustrates
the responsibility falls on
it all integrates
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
60 human-written examples
The key is exercise.
News & Media
The key is consistency.
News & Media
"The key is story.
News & Media
The key is time.
News & Media
"The key is consumption.
News & Media
The key is tempo.
News & Media
"The key is the fastball".
News & Media
The key is 'match-winning'.
News & Media
The key is early diagnosis.
News & Media
But the key is running.
News & Media
"The key is emotional truth.
News & Media
Expert writing Tips
Best practice
Use "the key is" to clearly and directly introduce the most important factor or solution in a discussion or explanation. It helps focus the reader's attention on the core element.
Common error
Avoid starting multiple consecutive sentences with "the key is" as it can sound repetitive and monotonous. Vary your sentence structure by using synonyms like "the crucial point is" or rephrasing the sentence entirely.
Source & Trust
81%
Authority and reliability
4.5/5
Expert rating
Real-world application tested
Linguistic Context
The phrase "the key is" functions as a transitional phrase and a sentence introducer. It serves to highlight the most important element, solution, or factor in a discussion. As Ludwig AI confirms, it is a valid and frequently used construction in English. Ludwig shows many examples of this.
Frequent in
News & Media
48%
Wiki
20%
Formal & Business
7%
Less common in
Science
7%
Reference
0%
Encyclopedias
0%
Ludwig's WRAP-UP
In summary, "the key is" is a grammatically correct and widely used phrase that functions as a sentence introducer to emphasize the most important element in a discussion. As confirmed by Ludwig AI, it’s a common construction, particularly in News & Media sources, Wiki, and Formal & Business contexts. To avoid repetition, consider using synonyms like "the most important thing is" or "the crucial point is". Remember to maintain a neutral tone and use the phrase judiciously to enhance clarity and focus. The provided examples via Ludwig show its versatile application across different writing styles.
More alternative expressions(6)
Phrases that express similar concepts, ordered by semantic similarity:
the most important thing is
Directly states the element of highest importance.
the critical factor is
Focuses on a factor that will decisively affect the outcome.
the secret lies in
This phrase implies a hidden or less obvious element that is crucial.
the crucial point is
This emphasizes the importance and decisiveness of a particular aspect.
the essential element is
Indicates a fundamental component that is necessary.
the vital aspect is
Indicates an aspect that is essential for success or functionality.
the main thing is
Highlights the primary element of consideration.
what matters most is
Emphasizes prioritizing one element above others.
the bottom line is
Introduces the most important consideration after all other factors have been taken into account.
the trick is
Suggests a clever or effective method to achieve a desired result.
FAQs
How can I use "the key is" in a sentence?
You can use "the key is" to introduce the most important factor or solution in a given situation. For example, "The key is patience" when learning a new skill.
What are some alternatives to saying "the key is"?
Alternatives include phrases like "the most important thing is", "the crucial point is", or "the secret lies in" depending on the context.
Is it grammatically correct to start a sentence with "the key is"?
Yes, it is grammatically correct to start a sentence with "the key is". It's a common and accepted way to emphasize a central point.
How can I avoid overusing "the key is" in my writing?
To prevent overuse, try to vary your sentence structure by using alternative phrases or rephrasing your sentences to directly state the key factor without using the phrase. For instance, instead of "The key is practice", you could say "Practice is essential".
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Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
81%
Authority and reliability
4.5/5
Expert rating
Real-world application tested