Л32
(А) ЛАРЧИК ПРОСТО ОТКРЫВАЛСЯ (sentpast or pres
fixed WO some seemingly difficult problem turned out to have a simple solution, some seemingly inexplicable phenomenon turned out to have a simple explanation etc
the explanation (the solution, the answer (to the puzzle)) was quite simple (after all)
it was easy (wasn't hard) to figure outthe reason was (all) too obvious.
From Ivan Krylovs fable "A Little Box" («Ларчик»), 1808.