-Where are the English books?    ---Sorry, ___.

A I know     B I don’t know    C it isn’t    D they’re not

-Where are the English books?    ---Sorry, ___.
A I know     B I don’t know    C it isn’t    D they’re not

—Mike, I don’t know            nice cartoon books.

—Why not go to the bookstore near my house? The books there are both cheap and nice.

A. where to buy                 B. what to buy                  C. when to buy