下列各组转化中，一定条件下均能一步实现的组合是（   ）

根据短文理解，选择正确答案。

    We talked to 300 people. One hundred were from 11 to 18 years old. One hundred were from 19 to 26. One hundred were 27 to 35 years old. We asked them what they like to do on weekends. Please look at the chart.

    Favourite things to do (by age).

在一定条件下，若物体运动的路程s（米）与时间t（秒）的关系式为s=5t²+2t，则当物体经过的路程是88米时，该物体所经过的时间为（　　）

法定义务是宪法和法律规定的公民必须履行的义务。以下言行中，能体现公民自觉履行法定义务的是（    ）