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 compulsory 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。）