"Did you read today's newspaper ?"
Can someone explain why we need 了 here? is it to specify that the action has ended?
今天的报纸 is the object of the verb, not an adverbial, and so goes after the verb, not before it, as I understand it.
I believe so. I almost did the same thing as per chinese grammar but realized jin tian is an adjective of bao zhi and not a preposition of kan