Gerunds? Past Progressive? Huh?

Sometimes I think I am learning more English than Japanese here. Confused? Well, let's think about this. In the USA, we grow up learning English, yet we are never really taught very specific grammar rules/the origins of the grammar/the proper name for the grammar point/why we use that grammar unless we take specific grammar based courses in maybe college, which I never did. Obviously I am a native speaker (duh), but being a native speaker only allows me to properly use grammar, not automatically understand why. This isn't really a problem in my lower level-middleish (improper use right there) level classes I teach just because the grammar points are kind of straight forward. However, this poses a problem every now and then in my upper level classes, where the grammar points become very very picky. In fact, half the time I look at the lesson point title in the textbook (see title of my blog for examples) and go "what the heck is ...?" Then, I read the explanation and go "ohhhh...ok." However, reading the explanation and connecting the dots doesn't necessarily make it easier to teach. ESPECIALLY in my advanced classes. Here is something you must understand about Japanese students- they don't really ask questions until they become advanced. I don't know if it's because they don't know how to ask, or are nervous or afraid of me or what, but a lot of times I have to force questions out of my lower level students because I KNOW they don't get it even though they are pretending they completely understand. However, the opposite goes for advanced students. They are not afraid to ask questions, that's for sure. And that is great and all, except sometimes they scare the crap out of me. It is bad enough when I have just spent the last thirty minutes to an hour learning THEIR lesson, and try to teach it the best I can with as much knowledge on the subject as possible...to then give a big fake/cheery (secretly paranoid/afraid) smile after finishing my confusing explanation, look at their (what I deem judgmental just because sometimes I think they have studied proper English more than me although I think I am just paranoid) faces and ask my most dreaded question, "Are there any questions?" And then have all hands shoot up, while I have the urge to cover my face and run away. What is scary about being asked questions by advanced students is they seem to choose questions about situations with the grammar point that basically have a .0000000001% chance of ever happening, and therefore completely catch you unprepared and off guard. Yet, because I am after all their teacher they pay thousands of dollars for in order to gain my English wisdom, I have to explain anyway as though I have spent two years of my life studying that very exact question. Half the time I have to repeat the question/phrase under my breath a dozen times to figure out how it would even be used let alone where/when. It also doesn't help that the textbooks are written by Japanese people (yes, that is correct, Japanese people write the English textbooks in English) and are not always correct, so I have to sit down with my coworkers (normally because this grammar is so specific and nit picky I am usually not the one to notice it is incorrect might I add) and figure out the correct way to explain it, which then causes an extra pile of questions since the students studied the incorrect lesson and are confused. It is an achievement if I get out of one of those classes with less than ten questions. Anyway, my whole point to sharing my ignorance of advanced English grammar with you is that every week I walk out of work with a stronger English education. I expect to be quite the expert when I return to the US in nit picky grammar as well as the grammar points proper titles (past continuous, gerunds, blah blah blah).