質問: recently I purchased a grammar book to help me prepare for the JLPT N3. One of the constructions I have come across is "〜てからでないと・・・." And I understand it's basic function (I think...). From what I understand it means something like "Unless A occurs B will/can not occur." I have come up with a few example sentences I'll place below. Please feel free to tell me if I have made any mistakes in my usage. 私は日本語がペラペラになってからでないと、日本の大学院に行けません。 毎日勉強してからでなければ、しけんにごうかくができません。 アメリカの人口がデモクラットのだいとうりょうをえらんでからでないと、しゃかいせいぎはしんぽしません。 However, after a few days of letting this grammar pattern mull around in my head I started to wonder if there are any inherent difference between the above grammar pattern and using a negative conditional followed by a negative main clause. For example is there a (big) difference between my first example sentence above and the following sentence: 私は日本語がペラペラにならないと、日本の大学院に行けません。 I've tried doing some preliminary research on this grammar point but have not been able to find much online in the way of explaining its nuances. If you know of any resources that got into this further I would greatly appreciate them. One thing I was also wondering is if this grammar would be something used in spoken language or is it more for written language? Also, if anyone knows a site the clearly identifies which grammar points are mainly used in written and spoken language that would be awesome. And finally if anyone could help me understand the construction of this grammar point that would be wonderful. From a literal perspective it seems like it means something like "(〜てから) after doing some verb (でないと) if it is not" or rearranged "if it is not after doing some verb." Like I think I can see where the are going with this but it is just not coming to me that intuitively. Again, any help you can provide is completely welcome and appreciated. :-)
回答: I believe that the ~てからでないと pattern has more chronological order implied. The basic meanings are similar. 一生懸命勉強してからでなければ、試験に合格できない。 一生懸命勉強しなければ、試験に合格できない。 Both have the same basic meaning of "If you don't study you won't pass". But the first one has a nuance of "taking the test once you have studied". Similar idea to 勉強してから、試験を受けないと合格できない vs 勉強しないと、合格できない。