I cannot seem to understand this for the various ways unless can appear in a sentence. I have been told to replace the unless with if not but also that the statement thats connected to the unless is the necessary condition. How can it be made an if not (making it sufficient) and also be necessary? Here are a couple of various ways I have seen unless in sentences: Unless I get a good grade, I will not go out; No student can go out unless they get a 4.0. To my understanding, you diagram these as follows:
If go out>>> got good grade
If student got 4.0, then they can go out
I gather these from sort of thinking about the relationship but I want a simple short cut to use. Any ideas?