She's involved in many extra-curricularactivities.
她参加了许多课外活动。
《牛津词典》
2
On the one hand, participating in extra-curricularactivities allows children to develop their hobbies while on the other hand, too many such activities can increase children's burden.
一方面，参加课外活动可以让学生发展自己的兴趣，而另一方面，太多的课外活动可能会增加学生的负担。
3
Participating in extra-curricularactivities enables us to learn to negotiate and cooperate with fellow students.