题目

根据短文内容，从下面选项中选出能填入空白处的最佳选项来补全短文。其中有一项是多余的。Everyone needs friends. But how do you find real friendship and keep it?The American writer Sally Seamans tells young students some smart ways to find friends.       16      . You plant the seed (种子) and take care of it to make it grow.First, you should choose a friend. What makes a good friend? It is not because a person has money or good looks.         17         For example, if you have a bad day, a good friend could listen to your co已知二次三项式x2+px+q的常数项与（x-1）（x-9）的常数项相同，而它的一次项与（x-2）（x-4）的一次项相同，试将此多项式因式分解．