幂函数f（x）=xⁿ的图象过点 $\left(2,\sqrt{2}\right)$ ，则f（9）=____ ．

将质量为W₁g的钠、铝混合物投入一定量的水中充分反应，金属没有剩余，共收集到标准状况下的气体V₁L。向溶液中逐滴加入浓度为amol·L^-1的HC1溶液，过程中有白色沉淀产生后又逐渐溶解，当沉淀恰好消失时所加HC1溶液体积为V₂L。将溶液蒸干充分灼烧得到固体W₂g。下列关系式中错误的是（   ）

①珍视当下，把握机遇   ②从小事做起，不懈努力

③树立理想，明确目标   ④发展兴趣，开发潜能

阅读短文，下列问题

B

    Andy plays basketball for the children's basketball club. He usually gets up at around 5:30 and runs in his school from 5:40 to 6:40. After running, he has breakfast at 7 o'clock. For breakfast, he eats some eggs and vegetables. At around 8:00, he plays basketball with his friends. They play basketball for around four hours. At about 12:00, they have lunch. For lunch, Andy has lots of vegetables, chicken and fruit. At 3 o'clock in the afternoon, Andy goes to the children's basketball club. He is never late for the club. Then Andy has dinner at about 7:00. After dinner, he watches basketball games on TV. Andy usually goes to bed at 10:30.