expression
among them; some of them
Used to single out a subset from a larger group, often with a contrastive or emphatic nuance. Typically followed by a statement about that subset.
クラスにはいろいろな生徒がいる。中には、毎日三時間勉強する人もいる。
There are various students in the class. Among them, some study for three hours every day.
この店のケーキはどれも美味しいが、中にはちょっと
All the cakes in this shop are delicious, but some of them are a little too sweet.