今年秋季开学以后，全国中小学生每天都要跳校园集体舞。新编的校园集体舞共分七套，每套舞蹈大约4至5分钟，将安排在每天课间休息和课外活动时间进行。

请看《中国日报》相关报道：Primary and secondary school students will dance into the new semester when the activity becomes compulsory¹ nationwide from September 1.

Seven sets of group dances have been designed to "suit the physical and psychological characteristics of students at different ages". Each dance set lasts 4-5 minutes, and will be performed during class breaks or in extra-curricular time .

报道中的“extra-curricular time”指的就是“课外活动时间”，相应的，“extra-curricular activities”则是我们自小都在接触的“课外活动”。

所谓“课外活动”就是学校里不包括curricular（正规课程）在内的各项活动，说白了，就是除必修课外再“额外附加”（extra-）的活动。

“额外附加的”，“在…之外的”可用前缀extra-来表达，英语中类似的合成词如：extramarital love（婚外恋），extra charge（附加费），extra income（额外收入）。

看下面一个例句：She's involved in many extra-curricular activities, such as music, sport and drama.（她参加了许多课外活动，如音乐、体育运动和戏剧。）