Twelve students in our class __ __ __take part in the summer camp last year.去年,我们班的十二个学生被选中去参加了夏令营.（中译英）

Twelve students in our class __ __ __take part in the summer camp last year.去年,我们班的十二个学生被选中去参加了夏令营.（中译英）
Twelve students in our class __ __ __take part in the summer camp last year.去年,我们班的十二个学生被选中去参加了夏令营.（中译英）

Twelve students in our class __ __ __take part in the summer camp last year.去年,我们班的十二个学生被选中去参加了夏令营.（中译英）
were chosed to