根据句意和所给的首字母提示，补全句子中的单词。

1．It is a p         letter，and you can't read it．

2．Don't give up．You know hard work leads to s        ．

3．F         has the fewest days of all the months．

4．P         future can be difficult．You never know what will happen in twenty years．

5．Italy is an E         country．