在物理实验中，经常要进行多次测量，其目的有两个：①为了减小误差；②是为了寻找规律．在“测量小灯泡不同电压下的电功率”的实验中，多次测量的目的是　 ____　（选填“①”或“②”）；在“用电压表和电流表测量导体的电阻”的实验中，多次测量的目的是　 ____（选填“①”或“②”）．

一组正方形按如图所示的方式放置，其中顶点B₁在y轴上，顶点C₁、E₁、E₂、C₂、E₃、E₄、C₃…在x轴上，已知正方形A₁B₁C₁D₁的边长为1，∠B₁C₁O=60°，B₁C₁∥B₂C₂∥B₃C₃…则正方形A₂₀₁₆B₂₀₁₆C₂₀₁₆D₂₀₁₆的边长是（　　）

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下面画一横线，并在该词下面写出修改后的词。

注意：1）每处错误及其修改均仅限一词；

2）只允许修改10处，多者（从第11处起）不计分。

    I woke up lately yesterday because my alarm clock didn't ring. With no time for the breakfast, I rushed out of my house. I had intended to catch the 7:30 subway, and I didn't make it. Have a little time left, I take a taxi instead. I arrived at the school only find, with great sadness mixed with some relief, that the school where should have been full of students was empty. It was Saturday. However, our ill luck showed no sign of coming at an end. When I returned home, I found myself lock out. I had left my key at home. Just my luck.