How often do they go to the library? Can he check out books? To read when?
Can he do something else during basic phonics work? (I assume he is reading well.)
Do they have advanced books in the classroom?
(They had advanced books in DD's library as well--but they hardly ever went there. The ones in the classroom went up to very easy chapter books, like 2nd grade level, which I think were brought in just for her. They were bad, like "Barbie Has a Party" sort of thing. The higher level picture books were better, honestly. More should have been done. Also, she was not allowed to sit out "The rat is on the mat," which was a crime. She entered K reading at about a 4th grade level, give or take.)
