【答题库最新整理国开(电大)人文英语3-1379网上形考机考题库】Lifelong learning is both formal and non-formal; and the boundaries between face-to-face teaching and ___________ education are

【答题库最新整理国开(电大)人文英语3-1379网上形考机考题库】Lifelong learning is both formal and non-formal; and the boundaries between face-to-face teaching and ___________ education are
increasingly blurred.
选择一项：
A. lifelong
B. formal
C. distance
译文：终身教育既是正规的又是非正规的，面授教学和远程教育的界限越来越模糊。