题目

阅读理解WhenJohn was growing up, other kids felt sorry for him. His parents always had himweeding the garden, carrying out the garbage and delivering newspapers. Butwhen John reached adulthood, he was better off than his childhood playmates. Hehad more job satisfaction, a better marriage and was healthier. Most of all, hewas happier. Far happier. Theseare the findings of a 40-year study that followed the lives of 456 teenage boysfrom Boston. The study showed that those who had worked as boys enjoyed happierand more productive lives than those who had not. Boys who worked in thehome or comm11、分解因式：ab2-2ab+a=a（b-1）2．