Translation:Dag. U spreekt met Roos.
Does "dag" mean "good bye?"
Why can't aan or naar be used instead of met?
I believe it's just a preference in usage. After all, it is in anticipation of a conversation, not a one-way speech. Also, from other exercises here, I believe instead of "naar" or "aan", it would be "tegen". "Hij spreekt tegen Roos."
I think you can also say 'Dag, met Roos' right ? At least i have heard people answering the phone like this