-- Hello, Tim! What's that?-- It's eraser.
A:a
B:an
C:the
D:不填
— How old is ____ (Tim, Kitty)?
— He's ten.
各项都是正数的等比数列{an}的公比q≠1,a3,a5,a6成等差数列,则a3+a4a4+a5=( )