heavy lifting
US /ˌhev.i ˈlɪf.tɪŋ/
UK /ˌhev.i ˈlɪf.tɪŋ/
1.
the most difficult or demanding part of a task or project
:
•
She did all the heavy lifting for the presentation.
•
We need someone to do the heavy lifting on this new project.
the most difficult or demanding part of a task or project