阅读理解
When the man's wife died, their baby was 2 years old. They had six other children -- three boys and three girls, aged from 4 to 16. The man's parents and his wife's parents came to visit. They said. “There's no way you can take care of all these children and work to make a living. So, we've decided to place each child with a different uncle or aunt.” The man refused.
His business developed quickly. He was happy to see people and serve them. He became popular with people for his kindness and excellent customer service. People came from far away to do business with him. And the children helped both at home and at work. Five years later, he moved the family to a tiny town and opened a small business. The children grew up and got married. Five of the seven went to college. The man took pride in his children. As they had children, he invited them to his workplace and his small home. They brought each other great joy. No one enjoyed grandchildren more than this man. Finally, the youngest daughter got married. After he finished his life work, the father died. This man's work had been the lonely but joyful task of raising his family. This man was my father. I was the 16-year-old boy, the oldest of seven.
根据短文内容，判断句子正误
行驶了全程的一半，然后匀减速行驶了后一半，恰好停止，全程的平均速度为 （ ）