1.he has been a soldier for 5years
he has(been )in the army ( since ) 5 years(ago )
2.Mr wang has taught english in this school ( since 1980)
(How )( long )has mr wang taught english in this school?
3.Actually,l didn't know him at all
( In )( fact ) l didn't know him at all
4.there have been great changes in our city( since he became the mayor)
How long have there been great changes in your city?
5.John has studied very hard in the past ten years(改为感叹句
How( hard John has studied )in the past ten years