Look, so many passengers _________ with their smart phones on the underground.
A：played
B：will play
C：are playing
D：have played
给下面的字选择正确的读音。
shě shè
有舍____才有得。
宿舍____前面种着好多花儿。
数列{an}中，已知对任意n∈N*，a1+a2+a3+…+an=3n﹣1，则a12+a22+a32+…+an2等于（ ）
