老师们通常要花费大量的时间备课翻译英文spend on.
问题描述：
老师们通常要花费大量的时间备课翻译英文spend on.
答
Teachers usually need to spend a lot of time on praparing lessons.
老师们通常要花费大量的时间备课翻译英文spend on.
Teachers usually need to spend a lot of time on praparing lessons.