What unique characteristics do English interrogative sentences have?

English interrogative sentences or questions have some particularities in their word order, which can make them difficult for learners. However, the word order rule of S-V-O (subject–verb–object) still applies in most cases.

Note: Besides the question mark, the essential difference to declarative sentences is that in interrogative sentences, the subject exchanges the position with the verb or the auxiliary by inversion. Read the explanation:

• The following example uses a modal verb to compare the difference between a declarative and interrogative sentence:
  • Declarative: “We can see the castle on the hill.”
    • The modal verb ‘can’ occupies the second position in the sentence and hence follows the subject ‘we’.
  • Interrogative: “Can we see the castle on the hill?”
    • Here, the modal verb ‘can’ stands before the subject ‘we’, which in turn still comes before the main verb ‘see’.
      • Information: This exchange of subject and verb is called inversion. Have a look at the subject/verb swap for a detailed explanation.
• This comparison shows an example sentence in the present perfect simple:
  • Declarative: “Frank has lent me some money.”
  • Interrogative: “Has Frank lent me some money?”
    • The auxiliary verb ‘has’ is already present in the declarative sentence; thus, it exchanges its place with the subject ‘Frank’ in the interrogative clause.
• Interrogative and declarative in the present continuous:
  • Declarative: “They are living in Norway.”
  • Interrogative: “Are they living in Norway?”
    • Inversion also takes place in this statement.

What happens in sentences without an auxiliary verb?

Some declarative sentences, especially those in the present simple and past simple, only have a main (lexical) verb and no additional auxiliary verb. To turn them into a question, the auxiliary ‘to do’ must generally be inserted to establish the correct word order. Without the help of this auxiliary, the subject would have to swap positions with the verb in the interrogative sentence, resulting in a grammatically incorrect sentence formation. To resolve this difficulty:

Inserting ‘to do’

• The following example is in the present simple and does not contain an auxiliary verb:
  • Sentence without auxiliary: “My best friend Ellie loves cheeseburgers.”
  • When we make it a question, we must place ‘to do’ (in this case, ‘does’ because of the third person ‘she’) before the subject:
  • Interrogative: “Does my best friend Ellie love cheeseburgers?”
  • By inserting ‘does’, the correct sentence order, i.e., subject before the full verb, can be maintained. The following question would therefore be grammatically wrong:
  • Incorrect: “Loves my best friend Ellie cheeseburgers?”

Position of the verb ‘to be’

Careful with ‘to be’: This verb is an exception that does not need the auxiliary ‘to do’. A question is constructed by simply moving its position:

• Declarative: “My brother is taller than me.”
• Interrogative: “Is my brother taller than me?”
  • Here, the constituents of the sentence follow the exceptional word order verb–subject; ‘to do’ is not required.

What happens in questions with question words?

If interrogative sentences contain question words or particles, such as ‘where, when, why, what, how much’, these words generally appear at the beginning of the sentence. However, you have to distinguish whether you are asking about the subject or the object. There are the following differences:

• In object questions (which are interrogative sentences in which you ask about the object), the question word precedes the auxiliary verb and the subject that follows it:
  • “Do you work on weekends?”
    • Question without question word; the auxiliary ‘to do’ begins the sentence.
  • “Why do you work on weekends?”
    • Question with interrogative word that precedes the auxiliary ‘to do’.
  • “Can I get some information about the theatre?”
    • Likewise, the modal verb ‘can’ may appear at the beginning.
  • “Where can I get some information about the theatre?”
    • The question word ‘where’ starts the sentence before the verb ‘can’.
• In subject questions (where you ask about the subject), the auxiliary verb ‘to do’ is not needed, as the question word takes the position and function of the subject. This particularity typically happens with the question words ‘who’ and ‘whose’:
  • “Who knows our new teacher?”
    • In this instance, ‘who’ is the subject and precedes the full verb ‘knows’; thus, the sentence follows the general English word order rule S-V-O.
  • “Whose friend comes from Australia?”
    • Again, the subject (whose friend) is also placed before the main verb (comes) here.

Further explanations relating to ‘English interrogative sentences’

The following explanations relate to the topic ‘Use of interrogative sentences with subject and object questions’ and may, therefore, also be interesting:

• Imperative sentences in English
• Constituents of a sentence
• How to ask for possession with ‘do … have’
• List of exercises for training the word and sentence order