Dear Teachers,

        I'm learning Special Interrogative Sentence.  In grammar books the authors say the interrogative pronouns (who, whose, which and what) can be used as subject  and subject complement in special Interrogative sentences.  when the verb "be" is used, I think it's difficult to distinguish between subject and subject complement because they have the same structure.  For example:

      In "Which is yours?" someone says "which" is the subject. 

       In "Whose beautiful antiques are these?" someone says "Whose beautiful antiques" is the subject complement.  But how to determine a interrogative pronoun is subject or subject complement in Special Interrogative Sentence when "be" is used?  They have the same structure:

      What (which, whose, who) be ..........

        Some examples like the structure:

         Which color is this?     What book is this?    Who are you?   What 's your name?    What's your hobby?   Whose book is this?

          The interrogative pronouns are subjects or subject complements?  How to distinguish them?  Please explain carefully.  Thank you.

Dear Teacher,

      Thank you!  But there is very interesting question:

       About your last example, can I answer like this:

        An example of an even number is twenty-six. 

        What do you think of this kind of answer?  Still a subject?  There sre two sentences:

         Chess is my hobby.

         My hobby is chess.

          The difference between them?  Please explain carefully.