{"id":2415,"date":"2021-05-23T15:23:37","date_gmt":"2021-05-23T09:53:37","guid":{"rendered":"https:\/\/www.rangakrish.com\/?p=2415"},"modified":"2021-05-23T15:52:26","modified_gmt":"2021-05-23T10:22:26","slug":"the-structure-of-wh-questions","status":"publish","type":"post","link":"https:\/\/www.rangakrish.com\/index.php\/2021\/05\/23\/the-structure-of-wh-questions\/","title":{"rendered":"The Structure of WH-Questions"},"content":{"rendered":"

WH-Questions<\/strong><\/em> are questions that begin with the following words:<\/p>\n

– Who (\u201cWho came here yesterday?\u201d<\/strong><\/em>)<\/p>\n

– What (\u201cWhat is the goal of this project?\u201d<\/strong><\/em>)<\/p>\n

– When (\u201cWhen can I visit my parents?\u201d<\/strong><\/em>)<\/p>\n

– Where (\u201cWhere did he go?\u201d<\/strong><\/em>)<\/p>\n

– Why (\u201cWhy is everyone running away?\u201d<\/strong><\/em>)<\/p>\n

– Which (\u201cWhich is the book you recommend?\u201d<\/strong><\/em>)<\/p>\n

– How (\u201cHow soon can you prepare dinner?\u201d<\/strong><\/em>)<\/p>\n

– Whose (\u201dWhose car is this?\u201d<\/strong><\/em>)<\/p>\n

– Whom (\u201cWhom should I contact for resolving this issue?\u201d<\/strong><\/em>)<\/p>\n

The WH-questions<\/strong><\/em> are usually asked to get detailed information, not a simple Yes<\/strong><\/em> or No<\/strong><\/em>. In contrast, we also have Yes\/No<\/strong><\/em>\u00a0questions<\/a>\u00a0that expect a Yes<\/strong><\/em> or No<\/strong><\/em> as answer. Some examples of this category are:<\/p>\n

– \u201cDid you have lunch?\u201d<\/strong><\/em><\/p>\n

– \u201cCan we go out for dinner tonight?\u201d<\/strong><\/em><\/p>\n

– \u201cDo you like coffee?\u201d<\/strong><\/em><\/p>\n

In today\u2019s article, I would like to go over the grammatical structure of WH-questions<\/strong><\/em> in English. The idea is not to propose a comprehensive grammar that covers all possible forms of the WH-questions,<\/strong><\/em> but to give a feel for what the structure looks like. For the present discussion, I will exclude \u201cWhose\u201d<\/strong><\/em> and \u201cWhom\u201d<\/strong><\/em>, and cover the remaining seven.\u00a0<\/span><\/p>\n

\"WH-Questions<\/a>
WH-Questions Structure<\/strong><\/figcaption><\/figure>\n

The above shows the grammar<\/strong><\/em> of WH-questions<\/strong><\/em> expressed as Definite Clause Grammar (DCG)<\/strong><\/em> in Prolog<\/strong><\/em>. It can be seen that each of the Wh<\/strong><\/em>-words is typically followed by an \u201cAuxiliary verb\u201d<\/strong><\/em>, a \u201cNoun phrase\u201d<\/strong><\/em> and a \u201cVerb phrase\u201d<\/strong><\/em> in that order. There are, of course, minor variations.<\/p>\n

What are \u201cAuxiliary verbs\u201d?<\/h3>\n

An auxiliary verb<\/strong><\/em><\/a>\u00a0is a verb that is used along with a \u201cmain\u201d<\/strong><\/em> verb to express tense, voice, etc. Some examples are am, is, are, have, do, did, being<\/strong><\/em>, etc. Modal auxiliaries<\/strong><\/em> are can, could, shall, ought, might<\/strong><\/em>, etc.<\/p>\n

– \u201cWhom <\/strong>should<\/strong><\/span> I contact for resolving this issue?\u201d<\/strong><\/em><\/p>\n

– \u201cWhere <\/strong>did<\/strong><\/span> he go?\u201d<\/strong><\/em><\/p>\n

– \u201cWhen can<\/span> I visit my parents?\u201d<\/strong><\/em><\/p>\n

– \u201cWhat <\/strong>is<\/strong><\/span> the goal of this project?\u201d<\/strong><\/em><\/p>\n

Noun and Verb Phrases<\/h3>\n

These two are known to have a very complex grammatical structure. What I have provided here are highly simplified structures. Elsewhere I have defined more realistic, although not complete, representations of these categories for my parsing needs, but that is not required for today\u2019s discussion. Feel free to refer to a good book on English grammar, for example [1, 2] to get an idea of how complex these can be. Here is the Noun Phrase<\/strong><\/em> description:<\/p>\n

\"Noun<\/a>
Noun Phrase Structure<\/strong><\/figcaption><\/figure>\n

Here are the Verb Phrase, Prepositional Phrase <\/strong><\/em>and Complementizer<\/strong><\/em> structures:<\/p>\n

\"Verb<\/a>
Verb Phrase, etc.<\/strong><\/figcaption><\/figure>\n

The final group consists of the primary parts of speech<\/strong><\/em> of various words:<\/p>\n

\"Other<\/a>
Other Categories<\/strong><\/figcaption><\/figure>\n

To validate the above structures, we can try giving sample WH-questions<\/strong><\/em> and check the output. I am using a Prolog<\/strong><\/em> clause \u201cparse_wh\u201d<\/strong><\/em> as the primary entry point. It uses a simple Tokenizer<\/strong><\/em> and then feeds the tokens to the DCG parser<\/strong><\/em> to get the result.<\/p>\n

\"Parser<\/a>
Parser Entry Point<\/strong><\/figcaption><\/figure>\n

Session-1: Where, When, Why<\/h3>\n
\"Where,<\/a>
Where, When, Why Questions<\/strong><\/figcaption><\/figure>\n

Session-2: Who<\/h3>\n
\"Who<\/a>
Who Questions<\/strong><\/figcaption><\/figure>\n

Session-3: What, How, Which<\/h3>\n
\"What,<\/a>
What, How, Which Questions<\/strong><\/figcaption><\/figure>\n

I trust the above discussion throws light on the top-level structure of WH-questions<\/strong><\/em>. I have implemented this in Sicstus Prolog<\/strong><\/em> (64 bit) running on Windows 10<\/strong><\/em>. You can download the above Prolog<\/strong><\/em> source file here<\/strong><\/em><\/a>.<\/p>\n

Have a nice weekend!<\/p>\n

Further Reading<\/h3>\n
    \n
  1. Randolph Quirk, Sidney Greenbaum, Geoffrey Leech, and Jan Svartvik, “A Comprehensive Grammar of the English Language”, Longman, 1985.<\/li>\n
  2. Rodney Huddleston and Geoffrey K. Pullum, “The Cambridge Grammar of the English Language”, Cambridge University Press, 2002.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    WH-Questions are questions that begin with the following words: – Who (\u201cWho came here yesterday?\u201d) – What (\u201cWhat is the goal of this project?\u201d) – When (\u201cWhen can I visit my parents?\u201d) – Where (\u201cWhere did he go?\u201d) – Why (\u201cWhy is everyone running away?\u201d) – Which (\u201cWhich is the book you recommend?\u201d) – How […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[107,17,147],"tags":[101,282],"class_list":["post-2415","post","type-post","status-publish","format-standard","hentry","category-natural-language-processing","category-programming","category-prolog","tag-definite-clause-grammar","tag-wh-questions"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p9OLnF-CX","jetpack-related-posts":[{"id":2131,"url":"https:\/\/www.rangakrish.com\/index.php\/2020\/09\/13\/mathematica-using-textcases-to-extract-information-from-natural-language-text\/","url_meta":{"origin":2415,"position":0},"title":"Mathematica: Using TextCases to Extract Information from Natural Language Text\u00a0","author":"admin","date":"September 13, 2020","format":false,"excerpt":"Extracting meaningful information from unstructured, human readable text is a hot topic of research today and has important applications in many domains. I have written a few blogs related to this topic, for example, see this\u00a0and this. In today\u2019s article, I would like to show how Mathematica can be a\u2026","rel":"","context":"In "Mathematica"","block_context":{"text":"Mathematica","link":"https:\/\/www.rangakrish.com\/index.php\/category\/mathematica\/"},"img":{"alt_text":"Extracting Sentences","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2020\/09\/ex1-2-300x106.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":2467,"url":"https:\/\/www.rangakrish.com\/index.php\/2021\/07\/04\/identifying-sentence-types-automatically\/","url_meta":{"origin":2415,"position":1},"title":"Identifying Sentence Types Automatically","author":"admin","date":"July 4, 2021","format":false,"excerpt":"Sentences in English can be classified into the following common types: - Simple sentence (\"I am drinking coffee\") - Compound sentence (\"He came home with his school friend and they had an enjoyable evening\") - Complex sentence (\"Whenever my dog barks, I give him some biscuit\") - Imperative sentence (\"Please\u2026","rel":"","context":"In "Natural Language Processing"","block_context":{"text":"Natural Language Processing","link":"https:\/\/www.rangakrish.com\/index.php\/category\/natural-language-processing\/"},"img":{"alt_text":"Top-level Predicates","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2021\/07\/code-300x233.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":1532,"url":"https:\/\/www.rangakrish.com\/index.php\/2019\/04\/07\/book-review-grammar-as-science\/","url_meta":{"origin":2415,"position":2},"title":"Book Review: Grammar as Science","author":"admin","date":"April 7, 2019","format":false,"excerpt":"Title: Grammar as Science Author: Richard K. Larson Publisher: The MIT Press Year: 2010 I love studying English Grammar. That is one of the reasons I enjoy working in the area of NLP. Machine Learning techniques apart, I firmly believe that a good understanding of the conventional approaches to modelling\u2026","rel":"","context":"In "Book Review"","block_context":{"text":"Book Review","link":"https:\/\/www.rangakrish.com\/index.php\/category\/book-review\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":4030,"url":"https:\/\/www.rangakrish.com\/index.php\/2026\/01\/27\/understanding-understanding\/","url_meta":{"origin":2415,"position":3},"title":"Understanding Understanding","author":"admin","date":"January 27, 2026","format":false,"excerpt":"What is understanding? Is it the same thing as knowing or is it different? In this short article, I want to gently explore this idea without getting philosophical.\u00a0 When we were school kids, we used to recite poems written by eminent authors without missing a beat. Of course, most of\u2026","rel":"","context":"In "General"","block_context":{"text":"General","link":"https:\/\/www.rangakrish.com\/index.php\/category\/general\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1410,"url":"https:\/\/www.rangakrish.com\/index.php\/2019\/01\/27\/generating-poetry-using-ilanggen\/","url_meta":{"origin":2415,"position":4},"title":"Generating Poetry Using iLangGen","author":"admin","date":"January 27, 2019","format":false,"excerpt":"In an earlier article, I wrote about using iLangGen to generate natural language text. iLangGen is a powerful text generation library that I have been working on over the years. Today, I would like to show how we can use that library to generate \"poetry\". Be warned, however, that the\u2026","rel":"","context":"In "LISP"","block_context":{"text":"LISP","link":"https:\/\/www.rangakrish.com\/index.php\/category\/lisp\/"},"img":{"alt_text":"Sample Output 2","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2019\/01\/Output2.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":870,"url":"https:\/\/www.rangakrish.com\/index.php\/2018\/03\/25\/question-answering-in-mathematica\/","url_meta":{"origin":2415,"position":5},"title":"Question Answering in Mathematica","author":"admin","date":"March 25, 2018","format":false,"excerpt":"About 10 days ago, I received an update for Mathematica. The latest version is 11.3.0. As usual, I looked through the list of new features\u00a0in this release. There are several new features, but one of them attracted my attention immediately: There is a new function FindTextualAnswer\u00a0that, given a piece of\u2026","rel":"","context":"In "Mathematica"","block_context":{"text":"Mathematica","link":"https:\/\/www.rangakrish.com\/index.php\/category\/mathematica\/"},"img":{"alt_text":"Example 1","src":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/03\/Example1.png?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/03\/Example1.png?resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rangakrish.com\/wp-content\/uploads\/2018\/03\/Example1.png?resize=525%2C300 1.5x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/posts\/2415","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/comments?post=2415"}],"version-history":[{"count":0,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/posts\/2415\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/media?parent=2415"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/categories?post=2415"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rangakrish.com\/index.php\/wp-json\/wp\/v2\/tags?post=2415"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}