How did you g____ there yesterday?

阅读短文，根据要求完成下面各小题。
    The students' life today can be very stressful (紧张的). They are under pressure (压力) every day. They need a (1)break from it. Parents should ask children to do something else. But not let them relax in front of the TV.  A hobby is the perfect answer.
    There are many different kinds of hobbies. Chess is a good example. It is a very enjoyable game and it also helps children develop their thinking skills.
    Collecting something is also a good hobby for children. A child can collect almost anything: key rings, stamps, postcards, old coins, etc. Many of these collecting can be both interesting and fun. They teach children a lot and broaden (开阔)their knowledge. For example, gardening (园艺) is a useful hobby because it is a physical activity and it also teaches children about nature.
    (2) A hobby can be a useful learning tool. Children may become experts in something if they really love their hobbies. Children will also learn to become more organized and make places, for example in collecting something. Hobbies will also teach children a lot about responsibility(责任).

最小的两位小数去掉小数点后，再缩小为它的 $\frac{1}{1000}$ 是____。

下列关于历史的说法，正确的是(      )

①历史是一条奔腾不息的长河，沟通了过去、现在和未来

②历史可以让我们追寻漫长的文明历程，洞察社会变迁的内在奥秘

③历史可以让我们审视千年的坎坷与辉煌，感受百年的悲怆与欢歌 

④历史是过去发生的事，讲的只是发生在过去的国内外重大事件

某中学举办电脑知识竞赛，满分为100分，80分以上为优秀（含80分），现将高一两个班参赛学生的成绩进行整理后分成5组；第一组50，60），第二组60，70），第三组70，80），第四组80，90），第五组90，100，其中第一、三、四、五小组的频率分别为0.30、0.15、0.10、0.05，而第二小组的频数是40，则参赛的人数以及成绩优秀的概率分别是（  ）