Look, sir, you know the landscape around here better than I do.
Slowly, sir, as though they knew who it was that had died.
Sir, I know of no way to put this politely.
"Good sir, I do not know your name to thank you properly."
"Maybe, sir, in another hour or two we'll know more of what is going on."
Sir, I do not know whether you are a qualified human being with respect to this order.
"Sir, our senior officer knows a few things about the subject, yes."
Also, sir, we don't know much about the other building, the one constructed hard against it.
Sir, I do not know who have never asked her.
Sir, you know full well I cannot answer that question.