be industrious/diligent/assiduous vs get down to business

be industrious/diligent/assiduous

get down to business

verb
  • To commit oneself to a task or activity that is employment-related or that requires serious effort or concentration. 

How often have the words be industrious/diligent/assiduous and get down to business occurred in a corpus of books? (source: Google Ngram Viewer )