p. 112, ex. 4
The girls usually skip every day because it is a good exercise if you like gymnastics. They are tired because they have been skipping for 30 minutes.
The boy usually plays football 3 times a week because he is interested in it very much. He is tired because he has been playing football for 2 hours. The boy is interested in boxing because it is a good kind of sport for boys. He is tired because he has been practicing for 3 hours.
The boys like karate because it makes them strong. They are tired because they have been practicing for 2 hours.
The girl is interested in swimming because it is a very good kind of sport. She is tired because she has been swimming for 2 hours.