已知函数$f\left(x\right)=x^2-ax$的图像在点$A\left(1,f\left(1\right)\right)$处的切线$l$与直线$x+3y+2=0$垂直，若数列$\left\{\frac{1}{f\left(n\right)}\right\}$的前$n$项和为$S_n$，则$S_{2013}$的值为 （     ）

用所给词的适当形式填空

（1）My mother often ____ (read) books after work.

（2）The boy ____ (ride) a bike to school every day.

（3）Mum always ____ (wash) clothes on Saturday.

（4）Li Kai  ____（have）a cool bag.

（5）My father never ____ (go) to work late.

老花镜的“度数”等于它的焦距的倒数乘100，请设计一个测老花镜度数的简单方法，要求写出所用器材、操作步骤和计算公式。