题目

阅读下面短文，从短文后各题所给的A、B、C和D四个选项中，选出可以填入空白处的最佳选项。Teens in the UnitedStates like teens in many countries have more leisure time today than everbefore. But over a number of decades, there have been some 1 in how teenagers spend theirtime after school.2 school clubs remains a common after-schoolactivity. According to a study, the three most popular are sports clubs,performing arts clubs, and academic clubs—the same as 20 yearsage. While overall participation in these clubs has gradually 3 over the last two decades,this d在中，内角对边的边长分别是，已知， （1）若的面积等于，求； （2），求的面积。