I was taught that doubt should be followed by 'whether/if' clause in declarative sentences and it should be followed by 'that' clause if it is an interrogative or negative sentence. But I found the following two sentences in Cambridge dictionary:
1. I doubt whether/if I can finish the work on time. (This is correc according to the grammatical rule).
2. [+ that] They had begun to doubt that it could be completed in time.
This is a declarative sentence but it is followed by 'that' clause. Could you please explain why?
Looking forward to hearing from you.
Thank you in advance.
Jiang
To me, "doubt if" is slang, and "doubt whether" is very formal.
I doubt if you can do it. (Slang, but very common)
I doubt whether you do do it. (Formal, not common)
I doubt that you can do it, or
I doubt you can do it. (Normal conversation.)
I don't like the rule you were taught. It doesn't reflect very well how we actually use "doubt."
Dear baqarah,
Thank you very much for your explanation. Now I see.
Best wishes,
Jiang
Quote:
Originally Posted by baqarah131
To me, "doubt if" is slang, and "doubt whether" is very formal.
I doubt if you can do it. (Slang, but very common)
I doubt whether you do do it. (Formal, not common)
I doubt that you can do it, or
I doubt you can do it. (Normal conversation.)
I don't like the rule you were taught. It doesn't reflect very well how we actually use "doubt."
doubt 
Linear Mode
