Translation:Medvědi to nevědí!
When is the proper time to use vědět and znát?
“Ví” should be accepted. This is the common spoken form.
It should not. It is not considered standard or "hovorový". You can check our authoritative resource http://prirucka.ujc.cas.cz/?slovo=v%C4%9Bd%C4%9Bt
Thanks - I am open to suggestions, but I’m going to check with some czechs.