How about:As a note, though, "doubt" is often a direct translation, particularly from Spanish, where it would be more common in English to use "question".
"I have a question about this sentence" would be a very common way of asking for help with a sentence.
To have a doubt about a sentence seems to point to the content of the sentence rather than the structure, as if you don't believe what the sentence says rather than having a problem with the syntax or grammar of the sentence.
How about:In BE we could certainly say I have my doubts about this sentence, which means the same as sentence 2.
I am sorry for for confusing you by my unclear words. I intend to find out which is the idiomatic preposition collated with "doubt" in this sentence.What do you think these sentences mean? That is important to know before answering the question.
In American English, these statements usually mean that you question the credibility or veracity of the sentence, not that you have a concern about how it is constructed.
I am sorry. I don't understand. Let me explain. I see the question in post 7 and you answer it is correct in post 8. I was wondering whether those preposition(about, on, over, upon, of) can used interchangeably in the same sentence.What are you intending to communicate with the word "doubts" in this sentence? If it's the same as above the best preposition is the one e2efour gave: "about". The others are not idiomatic, in my opinion.
There are indications that 'doubt' collocates with the preposition 'over', although not necessarily in "I have my doubts [preposition] this sentence."I intend to find out which is the idiomatic preposition collated with "doubt" in this sentence.
~ about , ~ over: Some committee members still had doubts about the plans.
have your doubts about something: They say they'll be here on time, but I have my doubts about that.
Thank you very much.