根据短文理解，选择正确答案。
Tonight, my piano recital(钢琴演奏会) was the most important thing in my family. My grandparents were coming by plane to hear me play. Even my busy Aunt Dianne, who is on TV every night reading the news, was coming.
But one thing was for sure. I would never win an award for my piano playing. And that's just because the more I practiced, the more nervous I got. So there I was，on the stage， in my beautiful dress，and I sat down at the piano. But when I started to play，I hit a wrong note. I told myself to start over. But then I hit the wrong note again. It was as if I hadn't practiced at all.
Finally the disaster was over. I ran off the stage. I couldn't understand why audience(观众) were clapping. But they were. My mom and dad had flowers for me and we were all supposed to go out for a nice dinner, but I couldn't. I just wanted to go home and cry and never go anywhere again. After we went back home, Aunt Dianne just came in and sat down on the side of my bed.
“It was my first night on the air,” she said. “I had never been on television before and I made a mistake. I mispronounced my name and the name of the news show. And you know what? No one even noticed but me. Just like tonight, no one noticed—just you.” Aunt Dianne was right. I think we are harder on ourselves than anyone else is. Maybe I will leave my room. And maybe I'll play the piano again.
2C(g)+2D(g)，在四种不同条件下的反应速
率如下，其中反应速率最快的是