2.根据本段的小标题“Plan your plan”和后文中的“They actually plan what they are going to do...set goals for what will be achieved”和“Set a plan”可知,A项“最优秀的学生不会只是随意坐下来完成学习任务”符合语境。
5.根据本段的内容尤其是下文中的“Just turn them off for an hour...Don't text your friends,don't chat while doing memory activities,don't make phone calls,just focus on what you're doing.”可知,G项“离开社交网站,关掉电话”作为本段小标题最佳。