These two words are used for sayingthat you are not certain about something, or that something may or may not betrue.
Perhaps is moreformal and is used in writing while maybe is used morein spoken English
e.g. I wondered if perhaps he had changed his mindabout attending the party.
e.g. ‘Whencan you give me an answer?’ ‘I don’t know. Maybe tomorrow.’
These two words can confuse evennative speakers. Probably is used forsaying that something is likely to be true, and possibly that it maybe true but you are not certain.
e.g. If house prices are low, it’s probably becausethere is a lack of demand.
e.g. ‘Wouldyou consider moving to another country for your work?’ ‘Possibly,I’m not sure.’
It is used when what you are sayingis based on what you have heard, not on what you know is true and thereforefact.
e.g. Apparently, she resigned because shehad an argument with her boss.
e.g. There is, apparently, going to be an announcement about the new CEO tomorrow.
4. As far as I know/ asfar as I am aware
These two expressions are used whenyou have partial (incomplete) knowledge of an issue or fact.
e.g. No one has complained, as far as I know.
e.g. As far as I am aware, theinvitations to the party have all been sent.
5. To the best of myknowledge
This phrase is used for saying thatyou think something is true, but you are not completely certain. This is quitea formal expression.
e.g. To the best of my knowledge, nosimilar book has been published.
6. Not to my knowledge
This is used for saying that youthink something is not true, although you are not completely certain.
e.g. ‘Hasthe report been sent yet?’ ‘Not to my knowledge.’
These are used when you thinksomething is probably true, but you can’tbe sure. “Guess” is morefrequently used in American English, although you can hear it in BritishEnglish, too. “Suppose” is morecharacteristic of British English and is often used in the negative.
e.g. I imagine they’ve already left for the airport.
e.g. I suppose she must be delightedabout getting the job.
e.g. I don’t suppose you’dconsider staying for another week?
e.g. I guess he will want to meetall the team members before the conference.