六年级英语的一道难题你能算出布朗先生儿子的年龄吗?Mr.Brown has five sons.They are Ted

六年级英语的一道难题
你能算出布朗先生儿子的年龄吗?
Mr.Brown has five sons.They are Ted,Tom,Bob,John.John has no elder brother and he was four years old when his first younger brother was born.Tom is very lucky.The number of his elder brothers is the same as his younger brothers.Jack will be 21 next year,and he is five years older than Bob.Bob is two years younger than Tom.Ted has no younger brother.There is 12 years betwwen him and John.How old are Mr.Brown's sons?
John______ Jack_____ Tom_________ Bob______ Ted_______