DD constantly asks a ton of questions (what 3 year old doesn't?), but often it's a question I don't have an answer for. Like a question about some specific thing she saw on tv or a daydream she had.... things I don't always know how to answer for her. She gets really upset when I tell her I don't know- "Please know, Mommy!" she tells me, and progressively gets more and more upset until I finally just make up something
I try to always be as truthful with her as possible, so making stuff up doesn't sit well with me. I've tried asking her what she thinks about whatever she's asking me, because I know sometimes kids ask questions when they really want to tell you what they think about something, but that's really not what she's wanting from me.