- 不可數名詞：僅單數形式，搭配單數形式動詞，其修飾詞為much, little, no
- work
- literature
- research
- information
- notation
- terminology
- equipment
- software
- hardware
- 可數名詞：有複數形式，修飾詞為many, few, no
- study --> studies
- paper --> papers
- researcher --> researchers
- investigator --> investigators
- 下列單字所引導的句子，也是僅存單數型式
- every
- each
- no
- another
- either
- neither
- one
