The Internet is very useful for us. We can _______ find information we need.

为了了解某年段1000名学生的百米成绩情况，随机抽取了若干学生的百米成绩，成绩全部介于13秒与18秒之间，将成绩按如下方式分成五组：第一组13，14）；第二组14，15）；…；第五组17，18．按上述分组方法得到的频率分布直方图如图所示，已知图中从左到右的前3个组的频率之比为3：8：19，且第二组的频数为8．

（Ⅰ）将频率当作概率，请估计该年段学生中百米成绩在16，17）内的人数；

（Ⅱ）求调查中随机抽取了多少个学生的百米成绩；

（Ⅲ）若从第一、五组中随机取出两个成绩，求这两个成绩的差的绝对值大于1秒的概率．

根据短文内容和首字母提示，在下文空格处填入适当的词使短文完整。在标有题号的横线上，完整写出空缺处所填单词的正确形式。
       Remember to be a good boy or a girl any time. It's i____  to have good manners, especially in some p____ places. When you are waiting in line, don't jump the queue. Be p____ . Don’t stand too close to others in the line. Keep 20cm a____  if you can.
     F____  the advice of the workers when your are having a visit on a place of interest. Do not climb on exhibitions. Make s____ it's OK to take pictures before you hold up your camera. When you go to shows, w____  clean clothes. You should get to the show 15 minutes before it starts. During the shows, turn o____ your cell phone. Don't eat during the show. Restaurants will be quite busy. Don't stay too long when you finish eating. Remember to t____ your rubbish away after the meal.
    Good manners can make you a g____ or a lovely lady. Wherever you are, others will be pleased with you.