Persistence is so hard in my opinion. Once I promised to persist on many things, but likely no one thing I could persist for long. I swore to lose my weight, then for a while, everyday I got up very early and ran for about 30min, and after one month, my weight was really lost. But once the winter was coming, it was so cold, I couldn't persist again, and you could guess that I gave up. I promised to improve my English, so I read some English books everyday, liked this, I also persisted for a while, but at last I still didn't persist for a long time. I wanted to learn more about my professional knowledge, I borrowed some books about our profession from our university library, and I read some of it, but I never read it again when I was busy doing my experiment, because I considered I was so busy to read now. In my life, just one thing I persisted to now, I was proud of it, it was letters which were wrote for my girl friend, I swore to write for her for 5 years, 3 years had past, I loved her very much.