"When does the class end?" in Engpsh can be expressed as "When is the class over?" or "What time does the class finish?"
The phrase "end" is a verb which means to bring to a conclusion, to finish. "Over" is an adverb that means finished, ended. "Finish" is a verb that means to complete, to bring to an end.
Here are some example sentences in Engpsh with their Chinese translations:
"When is the class over?" 什么时候课程结束？
"What time does the class finish?" 课程什么时候结束？
"The class ends at 3 PM." 课程在下午3点结束。