Except Tom, the other people all stay in the classroom.

除了汤姆，其他人都在教室里。(汤姆不在)。

youdao

His school will not let me involved in the classroom. I can't even go observe, except open school days.

他的学校不允许我陪读，除了学校开放日我也不能去观看上学的情况。

youdao

Everyone in the classroom, except the teacher, burst out laughing.

课室内每个人都放声大笑，老师除外。(只有老师没有笑)。

youdao

If you look back in time between now and the 1850s, everything in the world has changed except the classroom.

FORBES: Human with Machine Trumps Human vs Machine

No classroom time is required under the Wisconsin program except for clinical or practicum work for certain degrees.

WSJ: College Degree, No Class Time Required