This app is not very flexible. Often at the end of the sentence is more natural, but is marked as wrong.
I lived my whole life in an assumption that wardrobe and closet is the same thing, but the first one is British and the second is American. What a surprise...
They're only different for richer people and people that are into interior decorating. The implied but inconsistent distinction is that a wardrobe is a cabinet for clothing while closets are part of the floor plan as either a room or subsection of a room. Wikipedia offers this further erudition: Synonyms: (movable furniture for storing clothes): armoir, dresser; cupboard (UK); closet (regional US), press (Irish & Scots), shrank
I'm confused about when "동생" is used without a gender prefix and how frequently it is understood to mean little brother versus little sibling or little sister.
동생 is just in general a little brother or sister. But if you want to be exact, add 여 for a little sister (여동생) and 남 for a littler brother (남동생)