"Tomorrow afternoon in the classroom" 可以用 "tomorrow afternoon in class" 来表示。
"Tomorrow" 来自英语中 "to" 和 "morrow" 的组合，意思是 "明天"。
"Afternoon" 来自英语中 "after" 和 "noon" 的组合，意思是 "下午"。
"In class" 来自英语中 "in" 和 "class" 的组合，意思是 "在教室里"。
例句:
I will see you tomorrow afternoon in class.
(我明天下午在教室见你)
We have a meeting tomorrow afternoon in the classroom.
(我们明天下午在教室开会)
I will be teaching tomorrow afternoon in class.
(我明天下午在教室上课)