Why are brackets used in the first sentence?

• Brackets are used to add extra information about when the old theatre stood empty.
• The information in brackets, "(after it was damaged in a fire)," gives a reason for why the theatre was empty.
• This information is not essential to the main point that the theatre was empty for years.

Ответ: Brackets are used to provide additional information or clarification that is not essential to the main sentence.