阅读理解阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。 In the tenth grade，I began working for free at a vet's that was run by a friend. I wanted to get experience for what I thought would be my future job. However，on one particular Saturday morning I learnt something perhaps more important. The hospital was in the middle of one of the poorer sections of the city and some people could only pay for the most basic treatments. On this Saturday，a man and his young son，who was probably about 7 years old，walked in with a small cat in a