up
to develop or improve sth with some effort :
I can't work up any enthusiasm for his idea.
She went for a long walk to work up an appetite.
up
to develop or improve sth with some effort :
I can't work up any enthusiasm for his idea.
She went for a long walk to work up an appetite.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005