class的释义：
n.班;班级;课;上课;(某科目的)系列课程
vt.把…归入某等级;把…看作
adj.很好的;优秀的;出色的
例句：
Many children can't function effectively in large classes.
许多孩子在大班上课时学习效果不好。
We restrict the number of students per class to 10.
我们将每个班的学生人数限定为10人。
Our next class will take the form of a debate.
我们下一堂课将采用辩论的形式。
The class needs a minimum of six students to continue.
这个班最少需要六名学生才可以继续办下去。
Some teachers find it difficult to keep their classes in order.
有些教师觉得难以维持课堂秩序。
I have a history class at 9 o'clock.
我9点钟有历史课。