Economy can grow the general condition of reproduction on the rails continuously, it is the input quantity of every kinds of its discharge, must be more than sendout.
What I'm trying to demonstrate is the concept of comprehensible input, as did second language acquisition scholar Stephen Krashen did in this lecture of his.
We've tried everything else, we've tried grammar teaching, drills and exercises, computers, but the only thing that seems to count is getting messages you understand, comprehensible input.