When is the Dragon Boat Festival?为社么要用is 社么时候用does?

When is the Dragon Boat Festival?为社么要用is 社么时候用does?
When is the Dragon Boat Festival?
为社么要用is 社么时候用does?

When is the Dragon Boat Festival?为社么要用is 社么时候用does?
当谓语动词是行为动词是用does,当后面没有动词时而是名词时,用am,is,are.

When is the Dragon Boat Festival? When is the Dragon Boat Festival?

这句话的意思是“端午节是什么时候”如果不用is的话就是“当端午节……”does是用在三人称单数而且谓语动词是行为动词时用does