The Classification of Words

§ 407. The sentences He is a student — Is he a student? form a syntactical opposeme. Their forms differ >only in the type of intonation and the relative position of the members of the predication. The only difference in meaning is that between 'declaration' and 'interrogation'. These two meanings can be regarded as the manifestations of the general meaning of a grammatical (syntactical) category which has no name yet. The category shows whether the sentence is presented as a statement or as a question. Let us call it the category of presentation. Like any grammatical category this is a system of opposemes whose members differ in form to express only (and all) the particular manifestations of the general meaning of the category (§ 23).
The meaning of 'declaration' is expressed by a falling tone and by placing the subject before the predicate. The meaning of interrogation is expressed by a rising tone and by placing the structural (part of the) predicate before the subject.
Are you alluding to me? (Shaw). Shall I announce hini? (lb.). Is there no higher power than that? (Ib.). Do you call poverty a crime? (Ib.).
In the last example a special syntactical predicate, the syntactical word-morpheme do is introduced and placed before the subject.
§ 408. With regard to the category of 'presentation' Eng­lish sentences divide into those that have 'presentation' opposites and those which have not. Imperative and exclama­tory sentences mostly belong to the latter subclass-'In these sentences the opposeme of 'presentation' is neutralized. The member of neutralization (see § 43) usually resembles that of 'statement' (Go to the blackboard. Let us begin. Lookout!) But often it takes the form of the 'interrogation' member (Would you mind holding your tongue? (Hornby). Pass the salt, will you? Isn't she a beauty/) or an 'intermediate' form (How pretty she is!)
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§ 409. Not all interrogative sentences are syntactical opposites of declarative sentences.
The meaning of 'interrogation' in 'special questions' (otherwise called W/z-questions) is expressed either lexically ^: (when the subject or its attribute in a statement are replaced by the interrogative pronouns who, what, which or whose) or lexico-syntactically (when some other part of a statement is replaced by some interrogative pronoun). In either case they are not opposites of the corresponding statements because they differ lexically. Compare:

She Who
was thinking about you. (Shaw). was thinking about you?

Sweetie's Whose
thoughts were far from me. (Ib.). thoughts were far from me?

The horrible What
thought will break my heart. (Ib.) thought will break my heart?

B.

	is	The cat the cat?	is	on	the	tiles.	(Ib.)
Where

My son has become a thief. (Ib.)
has my son become?
She returned my love. (Ib.)

What did she return?