C 教室，课堂 a room in a school, college, etc.， in which a class meets for a lesson

　classroom　是可数名词，意思是“教室，课堂”。

　～ building　教室楼，教学楼
　～ capacity　教室容量
　～ instruction　课堂教学
　in the ～　在教室里

　The students left the classroom one after another.　学生们一个个走出了教室。
　When the teacher entered the classroom and saw two boys fighting, he cried: "Knock it off!"　教师走进教室看见两个学生正在打架，他喊道：“住手！”
　The headmaster glanced around our classroom.　校长环视了一下我们的教室。
　He was alone in the classroom.　唯有他在教室里。
　He forbids smoking in the classroom.　他不许在教室吸烟。
　He is repairing desks and chairs in the classroom.　他正在教室里修理桌椅。
　A teacher is responsible for the conduct of pupils in the classroom.　老师对学生在教室里的行为负责。
　The teacher stands in the front of the classroom.　教师站在教室的前部。
　My seat is in the fore part of the classroom.　我坐在教室前部。
　She came into the classroom on the sly.　她悄悄地进入了教室。
　He is never late for school, but he often comes into the classroom at the last moment.　他上课从不迟到，不过常常在最后一刻进教室。
　I shall meet you inside the classroom, not at the door.　我将在教室里面与你会面，而不是在门口。
　The boys rushed out of the classroom.　男孩子们从教室里冲了出去。
　He went out of the classroom outside the knowledge of his teacher.　他没告诉老师就溜出了教室。
　We will keep you out of the classroom if you make any noise.　你若喧哗，我们就把你赶出教室。
　The teacher considers homework a necessary complement to classroom work.　老师认为课外作业是对课堂内容的必要补充。
　Who is keeping the key to the classroom?　谁拿着教室的钥匙?
　Because of crowdedness, we had to stand outside the classroom.　因为拥挤，我们不得不站在教室外。