Stumped on a crossword clue? ‘I’ve ___ thinking…’ has you covered!

Stumped on a crossword clue? ‘I’ve ___ thinking…’ has you covered! - BEEN
"I've ___ thinking …"

Past participle of ‘be’
– Suggesting presence or existence
– Used to indicate duration of an action
– Something that has happened in the past and still has an impact
– Having a specific identity or quality
Occupied or engaged in certain activities

BEEN