English Grammar

I need someone to correct a couple sentences for me. Thanks
When using "forever" in a sentence......how would we use it wen talking about someone leaving his town forever.
John left his town for forever? or John left his town forever?
2ndly
which sentence is correct.
Why are you standing here? or Why you are standing here?
or
Why the gardener is not watering the plants? or why is the gardener not watering the plants?
theres no situation for the sentences.. just common translation problem.
The placement of the noun/pronoun or verb/help verb? a little bit of explanation would be appreciated.
Thank you.