根据句意和首字母提示完成单词。

1．-When do you often have a class m              ?

--On Friday afternoon．

2．I want to t               all over the world when I retire．

3．My home is c                 to my office, so I often walk to work．

4．T                     he is not rich, the old man feels very happy．

5．When we do cooking, we often use s                  ．It is necessary to our health．