When I was young, I liked to play jokes on people I knew, especially on my     1    and friends. One day my mother was cooking and I was     2     with my younger brother Tony. Suddenly I     3     to my mother and said,"Tony fell from the open window!" She was very   worried and ran out of the kitchen. Then I said, "Don't worry, I'm just joking"And my mother shouted at me, "    4     you do it again , I'll hit you."

Another day I went swimming with my friends in the sea. I wanted to play a joke on them. In the beginning, I swam     5    and I called out, "Help!" All my friends came to help me,    6     , they found that I was joking.

But half an hour     7     I wasn't joking. I was so fast    8     I got tired and couldn’t swim on in water. I tried my best to call my friends for help, but this time nobody came to help me.In the     9    They found I was telling the truth. They came and saved my life. They took me to the hospital. This is the best lesson in my life. From then on, I haven't joked on    10    .