Lily and Lucy are twin sisters. They come from America. They are in Canada now. Their parents find jobs( 工作 ) there. So they go to Canadian school now. They are ten years old. They go to the Red Apple School. They are in the same class now. Every day they go to school and come back home together( 一起 ). Their teacher , Mr Green , says to the students , “Please listen to me. You must write an English composition( 作文 )' My cat' this evening.” Lily is a nice girl. She writes the composition at home. But Lucy doesn't want to write it. And she is playing with a girl happily. The next day , Mr Green says to the class , “All of you write your composition. I read them at once( 马上 ) But two of you write the same composition.” Lucy stands up and says , “Lily and I are twins. So we have the same cat. Two cats are dirty( 脏的 )”. “All right. Please sit down. I know who can't finish the composition now , ”says the teacher.