alternation of bed

例句：

1. 1. The students are learning the new lesson through alternation of practice and lectures.
   学生们通过练习和讲座的交替学习新课程。
2. 2. The team will alternate between playing forward and defense positions.
   队伍将交替在前锋和后卫位置上比赛。
3. 3. The weather alternated between sunny and rainy days.
   天气交替出现晴朗和多雨的日子。