I find it so difficult to retrieve the dictionary form of all verbs used in duolingo. You need them to understand the forms are built up. For instance : this one : 싱거워요. What's the ....-다 form. 싱거우다 ? Can you help me ?
I'm wondering the same. I get the feeling that they are asking for the definition of the word "bland" because of they used "뭐". If I understand correctly, but again am not entirely sure, they would have used "무엇" to ask which things are bland.