I am not certain of what I am supposed to do. vs I am not certain on what I am supposed to do.

Both phrases are correct, but they are used in slightly different contexts. 'I am not certain of what I am supposed to do' is more commonly used and considered more formal. 'I am not certain on what I am supposed to do' is also correct but less common and may sound a bit informal.

Last updated: March 22, 2024 • 7090 views

I am not certain of what I am supposed to do.

This phrase is correct and commonly used in English.

This phrase is used to express uncertainty about what one is supposed to do. It is a formal and widely accepted construction.

Show examples from the web [+]

I believe that his family have succeeded in bringing him essential medicine, but I am not certain of this.
Captain, I am not certain I fully understand this Prospero character.
Mr Schulz, I am not certain we can discuss this point again.
I am not certain if they primarily serve Europe's interests.
I am not certain that is really a satisfactory answer.
I am not certain that human or Bajoran rites are fitting.
I am not certain, sorry.
I am not certain whether you are responsible for this area, so I would ask you to pass it on if necessary.
Mr President, I am not certain under which Rule I should now take the floor.
I have a suspicion that this is the case, but I am not certain.
Mr President, I am not certain I can follow the eloquence of Mr Fatuzzo in my explanation of vote.
I am not certain, personally, that this is a useful move, because I wish to take the debate to Turkey.
I assume he must have had a mother, but I am not certain.
Thus, I am not certain when I shall see you again.
Although I believe that the corpses were naked, I am not certain about this.
I am not certain about anything, and if you can't see that, we're even farther apart than I thought we were.
We lost our Stuart some years ago and I am not certain I could lose another child.
I am not certain, however, that reciprocation would be either helpful or fruitful.
I am not certain whether in the texts as they are worded now, sufficient distinction is being drawn between the two situations, in fact.
I am not certain that the directive is the proper instrument for this purpose.

Alternatives:

I am not sure what I am supposed to do.
I am unsure of what I am supposed to do.

I am not certain on what I am supposed to do.

This phrase is correct but less common and may sound informal.

This phrase is also used to express uncertainty about what one is supposed to do. It is less formal and not as widely used as the first phrase.

Show examples from the web [+]

Captain, I am not certain I fully understand this Prospero character.
Mr Schulz, I am not certain we can discuss this point again.
I am not certain if they primarily serve Europe's interests.
I am not certain that is really a satisfactory answer.
I am not certain that human or Bajoran rites are fitting.
I am not certain, sorry.
I believe that his family have succeeded in bringing him essential medicine, but I am not certain of this.
I am not certain whether you are responsible for this area, so I would ask you to pass it on if necessary.
Mr President, I am not certain under which Rule I should now take the floor.
I have a suspicion that this is the case, but I am not certain.
Mr President, I am not certain I can follow the eloquence of Mr Fatuzzo in my explanation of vote.
I am not certain, personally, that this is a useful move, because I wish to take the debate to Turkey.
I assume he must have had a mother, but I am not certain.
Thus, I am not certain when I shall see you again.
Although I believe that the corpses were naked, I am not certain about this.
I am not certain about anything, and if you can't see that, we're even farther apart than I thought we were.
We lost our Stuart some years ago and I am not certain I could lose another child.
I am not certain, however, that reciprocation would be either helpful or fruitful.
I am not certain whether in the texts as they are worded now, sufficient distinction is being drawn between the two situations, in fact.
I am not certain that the directive is the proper instrument for this purpose.

Alternatives:

I am not sure about what I am supposed to do.
I am unclear on what I am supposed to do.

What Our Customers Are Saying

Our customers love us! We have an average rating of 4.79 stars based on 283,125 votes.
Also check out our 2,100+ reviews on TrustPilot (4.9).

"Thank you!"
Sachi Nakama July 2024
"I have literally been through chat, PI, claude, bard and bing and I got conflicting answers! Thank you! Human intelligence reigns!"
Retha July 2024
"Faster than AI"
CYNTHIA December 2023
"This was very helpful and I personally think this site is the best."
Kaden October 2023
"It was extremely thorough and very helpful!"
imperialelisa October 2023
"7 years without any disappointment. Always 100% satisfied. You guys are the best in the world at what you do. Thank you so much :)"
Zubair Alam October 2023
"In a world of text messages and online communication, this is great to have as a live tool. Thank you."
Selena October 2023
"Without textranch I would be stuck!"
宏祐 October 2023
"Accuracy and fast response. Personal comments from editor. Thank you."
Clh September 2023
"I wasn't aware of this service, it's fascinating and more reliable than standard IA tools available on the internet"
Arturo September 2023
"The fact that you can get reliable fast feedback on your texts."
Vinicius Antonio August 2023
"you guys are better than grammarly i'm being honest here"
ordinary July 2023
"OMG! This is really good than any other text correction tools I've used so far. Highly recommend this."
Vehan July 2023
"Very fast and accurate. thank you."
mojtaba July 2023
"I love this app because it's help to writing skills all of students ♥️"
Tarisini July 2023
"This was exactly the mistake I was looking for, the wording dind´t sound right at first. Better than grammarly!"
Ente July 2023
"The immediate help that I received was reassuring and very satisfactory. Thanks."
priiiyanshuu July 2023
"this helps A LOT for my studies."
kathnunez02 June 2023
"Woow!! I would never have expected such precision! Thank you soooo much!!"
Berta June 2023
"Real Time Editor and not AI. Many Thanks."
Priya June 2023
"The very first thing excites me about Textranch is how much your editors care."
sepideh June 2023
"The fact that texts are checked by human editors rather than by AI, etc. I appreciate this!"
Анна June 2023
"Feel welcome, immediate response, high quality feedback"
martin.roy June 2023
"This is the best app that I have ever seen"
Burulai May 2023

I am not certain of what I am supposed to do. vs I am not certain on what I am supposed to do.