How do you use "have" in these sentences?
Has it not mentioned a time frame?
Has it not come to your ears?
...

Question

How do you use "have" in these sentences?
Has it not mentioned a time frame?
 Has it not come to your ears?
...

Answer

What is speaking in the sentence, "Has it not mentioned a time frame?"  A robot?  Normally a person speaks, so the sentence would be "Has he/she not mentioned a time frame?"

'Has it not come to your ears?" is not a correct English sentence.  Perhaps it should be something like, "Haven't you heard?"