She's involved in many extra-curricular activities.
她参加了许多课外活动。
《牛津词典》
2
Participating in extra-curricular activities enables us to learn to negotiate and cooperate with fellow students.
参加课外活动可以让我们学习如何与同学进行协商与合作。
3
On the one hand, participating in extra-curricular activities allows children to develop their hobbies while on the other hand, too many such activities can increase children's burden.