goes back
dates back; started in the past
Example: Our friendship goes back many years.
For more meanings of the phrasal verb go back, follow the link.
more information: go back
turned up
arrived
Example: He turned up late again.
For more meanings of the phrasal verb turn up, follow the link.
more information: turn up
on the doorstep
at the door; at the actual place
so to speak
You say so to speak to emphasise that what you've just said or about to say is unusual or idiomatic.
Example: She's been working her guts out, so to speak.
said
Here said is the past tense of the irregular verb say. Follow the link to find out more and to listen to examples.
more information: say
appropriate
Follw the link and listen to the way appropriate is pronounced when it's used as a verb.
more information: appropriate
stamp of approval
official approval; favourable regard
Example: The project is likely to go ahead, but I'll need the stamp of approval from the boss.