Both material nouns and abstract nouns belong to uncountable nouns. You can't add the indefinite article a/an before it and -s after it. Please remember the following typical uncountable nouns.

News information information consultation suggestions; Suggest progress; progress

Knowledge knowledge weather fun equipment

British furniture wealth wealth damage

Traffic flow, luggage of vehicles and pedestrians/luggage and clothing; clothes

Work work homework housework housework.

Description:

1. Some abstract nouns can be used with a/an to indicate something or someone when the meaning changes. These words include: surprise, pleasure, shock, honor, help, success and so on. When these words are used as predicative and object complement in sentences, their meanings will change, and a/an is usually added.

2. when paper means "paper", it is an uncountable noun, meaning "newspaper; Thesis; Examination paper; " "File" is a countable noun