work up

說真的，我不太了解work up
work up enthusiasm/interest/courage etc
to make yourself feel interested, brave etc
I'm trying to work up enough courage to go to the dentist.
work up an appetite/a thirst/a sweat
to make yourself hungry or thirsty, or make yourself sweat, especially by doing physical exercise
You can work up a really big thirst playing tennis.
work sb up
to make someone very angry, excited, or upset about something
work yourself up
You're working yourself up again.
She had worked herself up into a state .

work sth⇔up
to develop and improve something such as a project or a piece of writing
Jack took notes which he would work up into a report later.
work up to [work up to sth]
to gradually prepare yourself to do something difficult
work up to doing sth
He'd been working up to asking her for a date all week.