is not sure of

USAGE SUMMARY

The phrase "is not sure of" is correct and usable in written English.
You can use it when you are uncertain about something. For example: "He is not sure of the answer to the question."

✓ Grammatically correct

News & Media

Science

Human-verified examples from authoritative sources

Exact Expressions

36 human-written examples

He is not sure of his status.

The New York Times - Sports

He is not sure of the cause, though it could have been TB.

The New York Times - Health

For reasons he is not sure of, he also adds scallions at the end.

The New York Times - Food

Unlike the others, Keflezighi is not sure of his best event.

The New York Times - Sports

Despite being one of her firm's rainmakers, Teri is not sure of making partner.

The New York Times - Arts

Mr. Ford emphasized voters' unrest, telling the mostly Democratic audience: "The nation is not sure of us.

The New York Times

Human-verified similar examples from authoritative sources

Similar Expressions

20 human-written examples

Especially when one isn't sure of the candidates' names.

The New York Times

Even he isn't sure of the exact number.

Science Magazine

Is there one P.K.K.? I'm not sure of that".

The New York Times

Well, I'm not sure of that.

The New Yorker

And this I was not sure of".

The New Yorker

Expert writing Tips

Best practice

When using "is not sure of", ensure that the object of the preposition 'of' is clearly defined. Avoid ambiguity by specifying what the subject is unsure about.

Common error

Avoid replacing "of" with other prepositions like "about" or "on" unless the meaning is intentionally shifted to something else. Stick to "is not sure of" for expressing uncertainty.

Linguistic Context

The phrase "is not sure of" functions as an adjective phrase expressing a state of uncertainty or lack of confidence regarding something. Ludwig AI confirms that this phrase is grammatically correct and usable in written English.

Expression frequency: Common

Frequent in

News & Media

60%

Science

20%

Formal & Business

10%

Less common in

Academia

5%

Wiki

3%

Encyclopedias

2%

Ludwig's WRAP-UP

In summary, "is not sure of" is a common and grammatically correct phrase used to express uncertainty. Ludwig AI's analysis, combined with numerous examples from authoritative sources like The New York Times and The Guardian, confirms its widespread usage in various contexts, particularly in news and media, as well as scientific writing. When using the phrase, ensure clear definition of what the subject is uncertain about to avoid ambiguity. Alternative phrases such as "is uncertain about" or "is unsure of" can be used interchangeably, depending on the desired tone and level of formality.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

is not certain of

A direct synonym maintaining nearly identical meaning with a slight shift in emphasis.

is unsure of

A simpler and more direct alternative, replacing "not sure" with "unsure".

is uncertain about

Changes the preposition and uses a synonym for "sure" while maintaining the core meaning of lacking certainty.

is unconvinced of

Highlights a lack of persuasion or belief in something.

is doubtful regarding

Employs a more formal synonym and preposition, suggesting a higher degree of skepticism.

lacks confidence in

Shifts the focus to a lack of confidence rather than a lack of certainty.

is dubious about

Implies a questioning attitude and some level of distrust.

has reservations about

Indicates a more specific hesitation or concern about something.

is hesitant concerning

Uses a more formal tone to express reluctance or caution.

is skeptical of

Expresses doubt or disbelief, implying a critical assessment.

FAQs

How can I use "is not sure of" in a sentence?

You can use "is not sure of" to express uncertainty about something, like in the sentence, "He "is not sure of" the answer to that question."

What's a simpler way to say "is not sure of"?

A simpler way to say "is not sure of" is "is unsure of". Both phrases convey the same meaning of uncertainty.

Are "is not sure of" and "is not certain of" interchangeable?

Yes, "is not sure of" and "is not certain of" are largely interchangeable and convey the same meaning. The choice often depends on stylistic preference.

When is it appropriate to use "is not sure of" in writing?

"Is not sure of" is appropriate in both formal and informal writing contexts to express uncertainty. For instance, "The scientist "is not sure of" the exact cause of the phenomenon."