When using “until”, is the time mentioned inclusive or exclusive? Examples:  "I'm going to study until 8PM" Is he going to stop studying at 8PM sharp or 8:01PM?  "I'm not going to study until 8PM" Is he going to start studying at 8PM sharp or 8:01PM?  "I'm working until Friday" Does he stop working after his work on Thursday or Friday?  "I'm not working until Friday" Does he start working at Friday or Saturday?  "The kidnappers have given us until October 11th to deliver the documents" Do they need to deliver the documents before it hits October 10th or 11th?  From other similar posts, I learned that until is mostly exclusive but it can sometimes be inclusive but how do I tell exactly?
Is "until" inclusive or exclusive? I sent an email to someone and got an auto-reply saying:     I am out of the office until 09/15/2014.   Does this mean he will be available on the morning of the 15th?
Why do not we ask negative questions without a contraction on the not after the verb? I have found multiple questions touching on this but not a single one that has a comprehensive answer. The information is all there but in little bits.     etc.   Exactly why is "Do not you sleep?" ungrammatical (except in poetry/with artistic license)? I understand that not can't contract after you: "Do you not sleep?" because not can only contract after a verb, and that it always does after do: "Don't you sleep?" but why does it (why must it) contract if it's placed after the verb in a question?   Don't you sleep? (common form) Do not you sleep? (ungrammatical) Do you not sleep? (less common form)