本句想表達的意思是明天是星期天。tomorrow是將來的時間，應該是用將來時態來表達。即由助動詞will +動詞原型構成。那麼該肯定句就是Tomorrow will be Sunday.改為一般疑問句只要將will提到句首就可以了。改後為Will tomorrow be Sunday?否定句是Tomorrow will not be Sunday.

we are going to play baseball tomorrow是一個標準的一般現在時的句式，結構是be going to do something .因為有系動詞be,所以變為一般疑問句時直接把be提前就可以了，它的否定句就是直接在be後邊加not.還有一個就是人稱的變化，把we變成you.

Are you going to play baseball tomorrow?

Will it rain tomorrow? Yes,it will./No,it won't.

一般疑問句：AreyougoingtowatchTVtomorrow?題主提供的這個句子就是肯定句：IamgoingtowatchTVtomorrow.否定句：IamnotgoingtowatchTVtomorrow./Iwon`tgotowatchTVtomorrow.希望能夠幫到你，祝你進步，加油！