已知P是以F₁、F₂为焦点的椭圆$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1\left(a>b>0\right)$上一点，若$\overrightarrow{P{F}_1}·\overrightarrow{P{F}_2}$=0，$\tan \angle P{F}_1{F}_2$=2，则椭圆的离心率为（   ）

    On June 17,2012, my daughter gave me a new wallet as a Father's Day present. It was a perfect gift considering that my purse used for nearly a decade was much1 I took the opportunity as well to2some cards, notes, or small pieces of paper in it that were no longer needed. As I3out the old wallet, I was amazed at how much it4.Carefully I went through its5piece by piece and6them to their new home. As I was looking at them, I7 the organ donor card (器官捐赠卡) that I had signed nine years ago.8 it hadn't yet been called into use. Still, it felt good knowing that9 something should happen to me, I would be able to give another person a second chance of 10.

    As I11the card into my new wallet, I started thinking about all the 12things we can donate to help others today. We can donate our time, our talents or our wisdom. We can 13our kindness. We can 14 our light into the darkness. We can donate every bit of love and joy inside of us. And the greatest thing of all is that when we do, we15 that we have even more to share than when we start.

    Maybe you wish to 16an organ donor card so you can give something after you 17.But don't be afraid to give something now while you are still 18.Be a donor. Make your entire life a(n)19to others.Donate all your 20 things to make this world a better and brighter place.