There is a gramatical error in below mentioned sentece.According to grammar if sentence starts with if we put comma instead of then but u people always use both comma and then together why?????????????If only one of these statements is correct, then which one is it?
When you are using 'then' with a sentence that starts with 'if', you have to use a comma before 'then'. The sentence can also be written as 'If only one of these statements is correct, which one is it?'. In this sentence, 'then' is implied. Even if you mention 'then', the sentence will still be grammatically correct.