Jack's mother is ill. His father goes to New York and the boy has to look after her. He gets up early this morning, cooks breakfast for his sister and gives his mother some medicine  and water and then goes to school. On the way to school, Jack meets Bob, one of his friends. Bob asks, "Are you late this morning, too?" "Yes, I am." "I'm sure Mr. Brown will be angry at us," says Bob, "We can't go to school." "Where are we going, then?" "To the zoo. There are many monkeys in it. We'll have a good time there." "We can't do that," says Jack, "or we'll fall behind  our classmates. Mr. Brown is good. He wants us to be good, too." Bob thinks Jack is right and they go to school. Jack is late for school because   _  .
he gets up late. he goes to the zoo. he meets Bob. he looks after his mother and sister.