⑴A friend sent the CDs to me.____ A.
⑵We can find information from books.____ B.
⑶Let's go to the library.____ C.
⑷This is a book about science.____ D.
⑸I want a Chinese book.____ E.
— Yes, she can.
①统一了六国 ②统一了度量衡 ③用楷书书写 ④确立了皇帝称号
数列an中,已知对任意正整数n,a1+a2+a3+⋯+an=2n-1,则a12+a22+a32+⋯+an2等于( )