A so ne? - Is that so? ( but insinuating to one's self with the ne)
A so^ desu ka? Is that right?
sayo^ = so^
A sayo^ de gozaimasu ka can be used instead of A so^ desu ka when wanting to talk in ultra polite language.
To desu ka - used with base II of a verb as in
ikiyo^to^ desu ka? You are going?
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