Basic Structures, Questions,
Do-Insertion, Negation, Auxiliaries,
Responses, Emphasis, Contraction
English noncomplex sentences have five basic structures: affirmative statements, negative statements, yes/no affirmative questions, yes/no negative questions, and content questions. Here are the symbols used to represent each structure, together with an example of each one:
|+ (affirmative statement):||You live here.|
|− (negative statement):||You don't live here./You do not live here.|
|yn+ (yes/no affirmative question):||Do you live here?|
|yn− (yes/no negative question):||Don't you live here?/Do you not live here?|
|wh/co (wh[-word] content question):||Where do you live? Why do you live here? When do you live here? (etc.)|
Here is the difference between yes/no questions on the one hand and wh/content questions on the other hand: wh/content questions can never be answered yes or no, whereas yes/no questions can be answered yes or no and usually are. Thus:
 Where do you live?—*Yes. [Totally ungrammatical.]
 Where do you live?—On Sixth Avenue. [Grammatical, and one of many possible answers.]
We pay close attention to whether any given clause contains the nonmodal auxiliary do. Adding do to a clause is known as do-insertion. Do appears where we would expect it to appear in negative statements—as the first part of the predicate, and just after the subject, as figure 3a reveals. But in the three interrogative structures—yn+, yn-, and wh/co—do appears before the subject:
 Do you live here?
 Don't you live here?/Do you not live here?
 Where do you live?