DUOLINGO, YOU USED THE WRONG WORD. "KHÔNG PHẢI....MÀ CÙNG KHÔNG PHẢI." Every time I translate the version without phải from English I get the above. I have no clue when to use the above version. Someone please enlighten me.
hay, hoặc, mà Why is it not hoặc this time? There are just two given things to differentiate between. Do you remember "Anh áy có con mèo hoặc con chó."? Any hints why to use "mà"? And just so that you know, there's a difference in "if also" (hovering hints) and "or" (translation).