part (mass noun) is close to "some", it means some but not all thing. a part (countable) is a separate piece of something that you can combine with other pieces. It has been always a problem for me ...
I’ve noticed that some people use an article with the word “part” and the bulk of them does not (at least at some web pages I skimmed through). Which is the correct variant? I think that parts of ...
When should I use "as part of", and when "as a part of"?