DD10 is the same way. She used to actually start crying if she looked at something and didn't immediately understand every nuance about it.
Now, she has a similar reaction to what you are seeing; "I don't know what you mean. I can't do it, etc etc etc."
It is only when the thing she is supposed to be learning looks interesting or seems to be necessary to get to what she wants does she put any effort into it at all. I think it has a lot to do with her rarely having to think much about school work, so not knowing that it is the norm for people to have to actually read the entire passage, or problem or whatever before knowing the answer.
I also think it is part of growing up. I see it all the time in my students, especially the ones who have never had a teacher/parent who wouldn't simply give them the answer if they said they didn't know. With time they realize that I won't give answers and they think about it and figure it out, but it seems to be a rather hard lesson to teach most kids, forget about those who rarely have to put much thought into school work.
