I really love football. I' m a member (成员) of our school football team (队) and I play four times a week. I also like swimming and I go swimming after school. I don't like basketball.

                                                                        Jack

    My favourite sport is basketball. I also like table tennis, but I don't play it at school. I go to a club (俱乐部) with my friends. I' m not very good at football.

                                                                        Anna

    Bicycle riding (骑自行车) is my fav0urite sport. I go to school by bicycle. I also like travelling (旅游) by bicycle and I-do it with my father. It's very interesting. I don't like football or" basketball.

                                                                     David

    I like football. It's really interesting. My two brothers are in our school football team and they help me. I don't like playing it with my friends.
                                                                    John.

 下列工具属于费力杠杆的是（　　）

阅读材料，完成下列问题。

材料一  根据国家统计局2012年2月22日发布的最新“2011年国民经济和社会发展统计公报”，2011年我国出生人口1604万，出生率为11.93‰；死亡人口960万，死亡率为7.14‰；自然增长率为4.79‰；出生人口性别比为117.78。

材料二  我国隔5年的65岁及以上人口增长示意图(65岁及以上年龄人口占总人口的7%，则出现人口老龄化)。