And then we have these three words, unless, until and without, where the rule that you want to memorize is that you will put whatever idea comes after that word on the left side of the arrow, but a negated version. So if not, is saying, you treat it like if, in that you put it on the left side, but you need to put the negated version. So returning to this paragraph, the first one we saw was only when, which is just like only if, it introduces a right side idea, a necessary condition. So helping students become independent learners has to be on the right side of the arrow. And that means being an effective teacher goes on the left. In our second sentence, we see until, which is an if not.