已知函数$f\left(x\right)=x^2+2bx$的图象在点$A(0,f\left(0\right))$处的切线L与直线x-y+3=0平行，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 （   ）.

⑴How many books do you have?  ____     A. I'm from America.

⑵How many ducks can you see?____        B. He's Mr Black.

⑶Can I use you pen?  ____                         C. I have sixteen.

⑷Where are you from?____                       D. I can see twelve.

⑸Who's that man?____                              E. No problem.