作为青少年学生，关心社会、了解社会。可以从关注时事政治做起，我们关注时事政治的正当途径主要有（    ）

①上网、听广播   ②道听途说   ③看电视、看报纸   ④小道消息

下列长度中最接近10cm的是(    )

A

    The Double Ninth Festival is a traditional (传统的）Chinese festival. It usually comes in October or November. On this day，people always wear the zhuyu (茱萸）plant. They usually climb mountains. Sometimes they go to see flower shows. The Double Ninth Festival is a festival for old people. People usually visit their parents and grandparents on this day. They often eat Double Ninth cakes together.

找出下列各图形中数的规律，以此类推，a的值为____．