有一渡船正在渡河，河宽200m，船在静水中的速度为4m/s，水流速度为3m/s，则船最短的渡河时间为____ s，船最短的渡河距离为____m．

进入青春期后，心理和生理都在发生迅速而明显的变化。我们对身体的变化变得更加敏感，心里也在充满了新奇和困惑。下面不属于青春期生理变化的是（）   

      Everyone has his problems to worry about.
      Son: I try to be a good son, but no matter how hard I try, my parents never seem to be satisfied. They think I should eat healthier food, I should wear nicer clothes, and I should get better grades. And according to them, my hari should be shorter, my room should be neater(整洁), and my friends should be more polite when they come to visit. You know it isn’t easy to be a teenager.
     Parents: We try to be good parents, but no matter how we try, our children never seem to be satisfied. They think we should wear more fashionable clothes, we should buy a faster car, and we should listen to more interesting music. And according to them, we should be more sympathetic(富有同情心的) when they talk about their problems, we should be more friendly when their friends come to visit, and we should be more understanding when they come late from a Saturday night date. You know it isn’t easy being parents.
根据材料内容，判断正误。