根据所给首字母及释义写出单词

1.(p ) the things that make water,air or soil dirty
2.(s ) something that you bring back from a holiday
3.(t ) to give somebody lessons about how to do something
4.(u ) a railway line under the surface of ground in a city
5.(W ) connected with the west part of the world
6.(o ) to ask for some thing in a shop or a restaurant
7.(g ) a unit of people or things

根据所给首字母及释义写出单词 根据英语释义和所给首字母,写出相应单词 根据句意及所给首字母提示，写出句中所缺单词。 根据所给首字母写出句中所缺单词 根据英文释义和首字母提示写出相应单词 根据释意及首字母写出单词 根据句意及首字母写出单词 根据首字母提示及英文释义拼写单词 根据释义写出单词 根据首字母写出单词。