figure out 解决;算出;想出
at the heart of 位于……的中心
early on 在早期;从事;经营;继续下去
wrestle with 全力对付;努力克服
refrain from 抑制;克制;忍住
discern v. 识别;领悟，认识
salutary adj. 有益的，有用的;有益健康的
elaborate on 详细说明;阐明
Question time:
1. What is learning paradox?
2. What's the function of floundering according to the research in the passage?