根据句意及首字母提示补全单词。
1. The m_________ Olympics started in 1896.
2. There are some f_________ students in our class. They come from Canada.
3. We should do more exercise to b_________ up our bodies.
4. Nothing is difficult in your study if you put your h_________ into it.
5. Jim feels s_________ in class because he went to bed too late last night.