For example, you'd have 3 lines: the original line, a translated line, and a "learning" line in between that would have the verbs in their non conjugated form, etc.
Example with your sentence:
Mata 8 dragónes verdes
Matar 8 dragón verde
Kill 8 dragons green
This probably isn't the ideal configuration, but I think the general idea has a lot of potential and would greatly help with language learning. It would also really shine for languages with different alphabets - eg for japanese the top line could use kanji/hiragana/katakana, and the middle line romaji.
I thought of this recently while watching a Japanese movie- my Japanese is very rudimentary, and having romaji+English subtitles while listening to the movie in Japanese would make me learn super fast.