classroom 
英 [ˈklɑːsˌruːm]  美 [ˈklæsˌrum] 
n. 教室

例句：
It seems the problem lies in overcrowded classrooms and overstretched teachers. 

看来问题在于拥挤不堪的教室和过度疲劳的教师。

She makes literacy come alive in her third-grade classroom. 

她把三年级的识字课上得趣味盎然。