阅读理解。 Jack is an eleven-year-old boy. He has a father, a mother, a grandfather and two brothers in his family. Jack is the youngest ( 年龄最小的).  One of his brothers,  Tim,  is fourteen years old. T he other brother, Mike, is fifteen years old.  What's eleven and fourteen and fifteen? That is Jack's father John's age.  Jack's mother is very young. She gives birth to (生下) Jack when she is twenty-five years old. Jack doesn't know his grandfather's age. He is very old but very healthy. 根据短文内容,判断句子正(T)误(F). (     ) 1. There are seven people in Jack's family. (     ) 2. Jack doesn't have a sister. (     ) 3. John is thirty years old. (     ) 4. Jack's mother is twenty-five years old. (     ) 5. Jack's grandfather isn't old and he is healthy.