I would like to import texts and their translations from a single file. Could it be done? Is there any special character separating a fragment from its translation? Would like to import both simultaneously.

Sorry, but no, that’s not possible at the moment.

For what it’s worth, I imported text and just put up with whatever translation LingQ gives me (not bad objectively but could end up being annoying if you are sentistive about the story - I’m not really).