Go on and take it after opening (6)
I believe the answer is:
resume
'go on' is the definition.
(resuming is a kind of going on)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for resume that I've seen before include "Start or take up again" , "Abstract" , "Continue after a break" , "Speak again" , "list of achievements in Washington?" .)