Yes, the term "Ground Rule" is a proper term.
it is not correct English, you rather say still
It is correct.
It would be more correct to say, someone who.
It is correct English to say decent skill but not decent ability
It is correct English to say "He went off on a tangent".
Yes. Many people think there is a rule against ending a sentence with a preposition. If that were true, then it would not be grammatically correct to say, "Where are you from?" However, most grammarians do not think there is such a rigid rule. Although you could avoid the preposition at the end by saying "From where are you?", that is not how people actually speak and write English. So most would say that it is perfectly correct to say, "Where are you from?"
no it is not correct to say you are not for sure instead you can say in proper English that you are not sure about something
No. In English we say "How old are you?"
Yes, it is correct to say out of compliance with. It means out of help with in English grammar.
The correct phrase is ''everyone was'', as ''everyone'' is considered a singular pronoun and should be paired with the singular verb ''was''.
no you should say "Did you get an A on the English exam?"
Correct is the same as it is in English. It means that it is free from error.