What classes of words don’t have the concrete lexical meaning and possess the grammatical meaning only?

opposition – book::books (unmarked member/marked member)

8. 
   How can we define the grammatical category?
   

as the opposition between two mutually exclusive form-classes (a form-class is a set of words with the same explicit grammatical meaning).

9. 
   What is a set of words with the same explicit grammatical meaning?
   

10. 
    What is transposition?
    

is the use of a linguistic unit in an unusual environment

11. 
    How many approaches exist in classifying words into parts of speech?
    

There are four approaches to the problem:
1. Classical (logical-inflectional)
2. Functional
3. Distributional
4. Complex

12. 
    What are the criteria to distinguishing parts of speech?
    

semantic, formal and functional

13. 
    Сlassical approach distinguishes parts of speech into……