My name is Zhang Peng. I have a friend. His name is John. He has a grandpa and a grandma. They are seventy years old. They are at home. John's father works in a school. His mother is a doctor. John is a good student. They are very busy. They all get up early in the morning. John often helps his grandparents cook breakfast. There is a big garden and many young trees in front of his house. We can play games there. It's great.

如图，已知BD⊥AC，EF⊥AC，D、F为垂足，G是AB上一点，且∠FEC=∠GDB，

试说明：∠AGD=∠ABC．

下列句子有语病的一项是（     ）