通读下面短文，掌握其大意，然后从所给的A、B、C、D四个选项中选出一个可以填入短文空白处的最佳选项。
Ye Haitao, a 42-year-old man with paralysis (瘫痪) has helped over 300 children with school lessons for free over the last 20 years.
When Ye Haitao was young, he dreamed to be a (n)1, because he thought educating people was the greatest thing in the world.2 he was sixteen, he went to university in 1993. He studied hard to3 himself for his dream.
However,4 got in the way (阻碍) of Ye's study and life. In the second year of his university, he was so sick that he had to5 his study. Day by day, he couldn't walk, stand or even sit. He could only6 in bed all day.
One day some villagers came to Ye's home7 help. Many left-behind (留守) children in the village lived with their grandparents, but most of their grandparents could8 write or read. These children really needed help with their schoolwork at home, so Ye9.
Ye started helping these children in the summer of 1999. The students come to his home after school and during summer and winter vacations. They don't need to10 anything for the tutoring (辅导). Sitting at desk around Ye's bed, they always listen to Ye11.
Many of Ye's students have entered (进入) high schools and12 become college students. Seeing the children improve13 his help, Ye is quite happy. He knows he is doing a meaningful job. "It is the14 of these children that keeps me doing this. I get a strong15 of satisfaction when I see their smiling faces," Ye says.
