题目

On weekends,I often ____________ and watch TV.A.stay at home     B.go to school      C.join the club 答案：B解析:略如图所示的是由3个边长为1的正方形组成的图形．（1）则图中AB1=______，AB2=______，AB3=______（2）从（1）中请你寻找规律，当图形是由10个正方形组成时，求AB10的值（3）当图形有n个正方形组成时，求ABn的值．