A:have you been away from
B:did you leave
C:have you left
D:are you away from
读图,完成下列问题。
which; who; how heavy; whose; how tall
教室里座位整齐摆放,若小华坐在第四排第6行,用有效数对(4,6)表示,则(2,4)表示的含义是____ .