business - Is countable or uncountable?

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. We have an urgent business.
  2. We have an urgent piece of business.
  3. We’re now doing twice as much business as we did last year.
  4. How is (your) business?
  5. He has the skills necessary to start a business.
    Please correct the above.
    Please mention which word - ‘business’ is countable or uncountable noun?
    Thanks.
2

Usual rules apply - the countable noun takes an article.

  1. We have urgent business. (uncountable)
  2. correct. piece of business - countable (one piece, two pieces, etc.)
  3. correct. uncountable
  4. correct. uncountable
  5. correct. countable