must be

USAGE SUMMARY

"must be" is a valid phrase that is commonly used in written English.
You can use it to express necessity, obligation, or probability. Example: "This paper must be finished by Friday."

✓ Grammatically correct

News & Media

Wiki

Formal & Business

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

Those must be kids".

Independent

Tombs must be unearthed.

The New Yorker

Crimes must be solved.

The New Yorker

Must be Grant".

The New Yorker

This must be correct.

The Economist

Energy must be renewable.

The Economist

It must be overturned.

The New York Times - Magazine

They must be resisted.

The Economist

I must be strong.

The New Yorker

It must be considered.

The New York Times

Must be told".

The New York Times

Expert writing Tips

Best practice

To avoid ambiguity, ensure the context clearly indicates whether you're expressing a necessity or a strong probability. For example, "Applications must be submitted by Friday" (necessity) vs. "That must be John at the door" (probability).

Common error

Avoid using "must be" to present subjective opinions as facts. Using "must be" implies a logical conclusion based on evidence, not personal preference. For example, instead of saying "That movie must be good", which is subjective, provide reasoning like "That movie must be good; it has won several awards".

Linguistic Context

The primary grammatical function of "must be" is to express necessity, obligation, or probability. Ludwig AI notes this phrase is commonly used to convey a strong degree of certainty or logical conclusion.

Expression frequency: Very common

Frequent in

News & Media

73%

Wiki

13%

Formal & Business

5%

Less common in

Science

4%

Encyclopedias

0%

Reference

0%

Ludwig's WRAP-UP

In summary, "must be" is a versatile modal verb phrase used to express necessity, strong probability, or logical deduction. Ludwig AI confirms its validity and common usage in English. It appears most frequently in news and media contexts, carrying a neutral register suitable for both formal and informal communication. While the phrase is generally straightforward, it's important to ensure its use aligns with the intended meaning of certainty or obligation, avoiding subjective opinions presented as facts. Several alternatives, such as "has to be" or "should be", can be used to convey slightly different nuances. Ultimately, using "must be" correctly enhances clarity and precision in writing.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

has to be

Emphasizes obligation or necessity in a slightly more direct way.

has got to be

Similar to "has to be" but adds a slightly more informal and emphatic tone.

is bound to be

Expresses a strong likelihood or inevitability.

should be

Indicates a recommendation or expectation rather than a strict necessity.

is certain to be

Very similar to "is bound to be" but with a higher degree of confidence.

is required to be

More formal, indicating a requirement or regulation.

it is likely that

Expresses a probability or likelihood.

it is essential that

Highlights the importance or necessity of something.

presumably is

Indicates something is likely true based on available evidence but without absolute certainty.

it is imperative that

Similar to 'it is essential that' but conveys an even greater sense of urgency and importance.

FAQs

How can I use "must be" to show certainty?

Use "must be" when you can logically deduce something from available evidence. For example, "The lights are off; they "must be" out."

Is "must be" interchangeable with "should be"?

No, "must be" indicates a strong degree of certainty or necessity, while "should be" expresses a recommendation or expectation. The context determines which is appropriate.

Can "must be" be used to express obligation?

Yes, "must be" can express obligation, especially in formal contexts. For example, "All entries "must be" submitted by the deadline."

What's the difference between "must be" and "has to be"?

Both phrases express necessity, but "must be" is often perceived as slightly more formal than "has to be". In many casual contexts, they are interchangeable, but in formal writing, "must be" might be preferred.