阅读材料并回答问题。

材料一：“我个人爱好阅读、看电影、旅游、散步。说到体育活动，我喜欢游泳、爬山等运动，我还喜欢足球、排球、篮球、网球、武术等运动。冰雪项目中，我爱看冰球、速滑、花样滑冰、雪地技巧。”在接受俄罗斯媒体专访时，***这样介绍自己的兴趣爱好。实际上，历任党和国家领导人均有“个性化”的兴趣爱好。***爱好游泳、跳舞、乒乓球，邓小平爱好桥牌、球类运动。

材料二：某中学一位七年级的学生刚升入中学时，在班里的成绩名列前茅。不久，在他家的附近开了一家游戏厅，他开始到那里玩，后来就入了迷，放学就到游戏厅，学习成绩明显下降。后来因为没有钱玩游戏，开始从家中偷钱，向同学敲诈，最终被派出所拘留。

请回答：

动词填空 用括号内所给动词的适当形式填空。
⑴Mom makes me eat an apple a day ____  (keep) the doctor away.
⑵She spent as much time as she could ____  (explain) it to us, but we still didn’t believe her.
⑶I was told that some students in Grade Seven and Eight ____  (take) part in an English camp in
Australia the next month.
⑷I remember his brother ____  always ____ (ask) questions in class when he was at the primary school.
⑸The various fantastic drawings the famous artist devoted himself to ____  (show) in our school hall the day before yesterday.
⑹The girl sitting next to me on the plane was nervous, for she____  never ____  (fly) before.
⑺The number of deaths from heart disease____  (reduce) greatly if people eat more fruits and vegetables.
⑻“So Young”, a new movie directed by Zhao Wei, ____ (earn) about 600 million yuan in the last few weeks.

等差数列$\left\{a_n\right\}$中，若$a_2+a_8=15-a_5$，则$a_5$等于（   ）