Having returned from her round trip, the angry woman stood outside the ticket office of the station. "The railway should pay me backPS12, so you owe me the money," she said to Harry Jenks, the young man who was working at the office. "You sold me a ticket for May 22nd, but there was no ship from Jersey that night. So my daughter and I had to stay in a hotel. It cost me PS12." Harry was worried. He remembered selling the woman a return ticket. "Come into the office, Madam," he said politely, "I'll just check the Jersey timetable for May 22nd." The woman and her little girl followed him inside. She was quite right, as Harry soon discovered. There was no sailing on May 22nd. How could he have made such a careless mistake? He shouldn't have sold her a ticket for that day. Wondering what to do, he smiled at the child. "You look sun burnt," he said to her, "Did you have a nice holiday in Jersey?" "Yes," she answered, shyly, "The beach was lovely. And I can swim, too!" "That's fine," said Harry. "My little girl can't swim a bit yet. Of course, she's only three..." "I'm four," the child said proudly, "I'll be four and a half." Harry turned to the mother. "I remember your ticket, Madam," he said, "But you didn't get one for your daughter, did you?" "Er, well..."woman looked at the child, "I mean... she hasn't started school yet. She's only four." "A four-year-old child must have a ticket, Madam. A child's return ticket to Jersey costs...let me see...PS13.50. So if the railway pays your hotel, you will owePS1.50. The law is the law, but since the fault was mine..." According to the passage, we know that Harry was   _  .
careful hard-working serious smart