This is the 1245th most frequent Korean word.
학생들은
"Students"
Here, '학생들은' indicates the subject (students) who are performing the action of reading.
학생들은 책을 읽고 있습니다.
The students are reading a book.
In this instance, '학생들은' is used as the subject to specify who went to school.
학생들은 학교에 갔습니다.
The students went to school.
This sentence uses '학생들은' to highlight the subject (students) assigned the responsibility of studying hard.