Another type of informative sentence like the declarative is the interrogative sentence function. Much like declaratives, interrogatives are fairly common sentences in general English although they are much less commonly used in academic writing and speech. The function of an interrogative is for the speaker (or writer) to question the listener (or reader) about something unknown, or to request more information or assistance from that person. Simply then, an interrogative is a call for knowledge, as is shown in the following examples.
Academic Examples
– How are these findings significant?
– In which year did Germany invade Poland?
– What are the causes of the China-America trade war?
– Which variables were the most important in your study?
– What were the main motivations for European colonialism?
What can be seen from these examples is that interrogatives in academia may be used most commonly in essay questions, for the headings and subheadings of assignments, or for general comprehension and discussion questions. Where such interrogatives are hardly used in academic writing is when writing introductions, body sections and conclusions. This is because direct questions like interrogatives are considered too informal in an essay and are therefore seen as being unacademic.
Recognising Interrogatives
The easiest way to recognise a written interrogative is to look for the questions mark (?) placed at the end of that sentence, and in speech such sentences are often also marked with rising intonation. Additionally, interrogatives most often begin with either an auxiliary verb such as ‘do’ and ‘be’, or with an adverb such as ‘what’, ‘when’ or ‘why’, moving the subject out of its first position in the sentence. The change from a declarative to an interrogative structure can be seen below: