How to say how come you don't know this? in Japanese
1)
どうしてどうして(doushite) (adv,int) why?/for what reason/how/in what way/for what purpose/what for君君(kun) (pn) you/buddy/pal/monarch/ruler/sovereign/master、、(、) Japanese commaこのこの(kono) (n) thisことこと(koto) (prt) particle indicating a command/particle indicating mild enthusiasm/particle indicating a gentle interrogative/particle used to soften a judgment or conclusionをを(wo) (prt) indicates direct object of action/indicates subject of causative expression/indicates an area traversed/indicates time over which action takes place/indicates point of departure or separation of action/indicates object of desire, like, hate,知らno dictionary result, likely a conjigated verbno dictionary result, likely a conjigated verbないない(nai) (aux-adj) not/emphatic suffixのの(no) (prt) indicates possessive/nominalizes verbs and adjectives/substitutes for "ga" in subordinate phrases/indicates a confident conclusion/ indicates emotional emphasis/indicates questionかねかね(kane) (prt) interrogative sentence-ending particle expressing doubt？？(？) Japanese question mark
