but what i won't do is play ball.为什么is和play同时出现.play是系动词?

but what i won't do is play ball.为什么is和play同时出现.play是系动词?
but what i won't do is play ball.为什么is和play同时出现.play是系动词?

but what i won't do is play ball.为什么is和play同时出现.play是系动词?
应该是to play

这是口语~没什么语病可言