请问ball games算是单数还是复数?比如说 我说我喜欢球类运动.My favourite sports are ball games.是这样写的么?

请问ball games算是单数还是复数?比如说 我说我喜欢球类运动.My favourite sports are ball games.是这样写的么?
请问ball games算是单数还是复数?
比如说 我说我喜欢球类运动.
My favourite sports are ball games.
是这样写的么?

请问ball games算是单数还是复数?比如说 我说我喜欢球类运动.My favourite sports are ball games.是这样写的么?
双数