"Is this Teacher Wang's wife?"
No, you don't need the question participle at the end if you have the "verb no verb" section in the sentence.
Sometimes this language is so odd. Is not is, ya, thats not confusing at all.
English can be similar: ''You are Chinese, aren't you?'' or ''Isn't that cat cute? Yes it is!''
I like to imagine it as (is/isn't) box place that in front of anything and ur asking a yes o no question.
It is like they are saying "This is or isn't...?". If that makes any sense.