Writing about catasrofy

Last year I was going with my friends to an exotic Island and buy a boat. One day my and my friends going with boat to the see, when stay swimming and sunbathing, the big big wave reach my and my friens and the boat fall down. I'm swimming and swimming and I don't see nobody around my. My friends dead. I'm swim to the island. I'm stay 2 hours to regress at the island. When I'm stay in, I'm very sad and in my hard stay a very horrible story.