English Grammar : article, syntax, verbs conjugation, English spelling

Wh-questions are questions that begin with one of the eight “wh ” words: who, whose, what, when, which, why, where and how. Questions formed with “wh ” words ask about the word or phrase the “wh ” word replaces.

Who replaces pronouns and the names of people. When the question word is the subject, the word order doesn't change:

“Columbus discovered America in 1492.”
“Who discovered America in 1492?”

When the “wh ” word replaces a word in the predicate, and the verb includes a modal (such as “can,” “will,” “may”), a form of “to be,” or a form of the helping verb “have” the predicate and subject are switched:

“He is the president.”
“Who is he?”

However, when the “wh ” word replaces a word in the predicate, and the verb phrase does not contain a modal, a form of “be” or a form of the helping verb “have,” “do formation” is used:

WH- word + “do” + SUBJECT + VERB PHRASE

“Do” always takes the tense of the original verb, and the verb takes the base form:

“Jack hit the president.”
“Who did Jack hit?”

“Bill loves Mary.”
“Who does Bill love?”

“Whose” is the possessive form of “who,” and works the same way:

“Shakespeare's plays are well known.”
“Whose plays are well known?”

“That is Jack's dog.”
“Whose dog is that?”

The do formation is used when the verb phrase does not contain a modal, a form of “be” or a form of the helping verb “have.”

“Jack drove Bill's car.”
“Whose car did Jack drive?”

“What” replaces any noun or noun phrase that is not a person or pronoun. Questions are formed with “what” the same way as with “who” and “whose”:

“The car hit the dog.”
“What hit the dog?”

“Mary's favorite candy is chocolate.”
“What is Mary's favorite candy?”

The do formation is used when the verb does not contain a modal, a form of “be” or a form of the helping verb “have”:

“Bill bought a car.”
“What did Bill buy?”

“When” replaces time specific words (adverbials of time). When a modal, a form of “be” or a form of the helping verb “have” is used, the subject and predicate are simply switched.

“John's appointment was at four o'clock.”
“When was John's appointment?”

The do formation is used when the verb phrase does not contain a modal, a form of “be” or a form of the helping verb:

“John arrived at noon.”
“When did John arrive?”

“Which” is used when one object among several has to be selected. “Which” replaces the specific object identified:

“That car was involved in the accident.”
“Which car was involved in the accident?”

The do formation is used when the verb does not contain a modal, a form of “be” or a form of the helping verb “have.”

“The baseball broke that window.”
“Which window did the baseball break?”

“Why” does not replace any specific word or phrase in a sentence. Rather, “why” asks for the reasons an action was done. The clause in a sentence explaining “why” usually begins with “because....” When the verb is a modal, a form of “be,” or a form of the helping verb “have,” the subject and predicate are switched:

“Mary is thin because she went on a diet.”
“Why is Mary thin?”

The do formation is used when the verb phrase does not contain a modal, a form of the verb “be” or a form of the helping verb “have”:

“John missed the bus because he got up late.”
“Why did John miss the bus?”

“How” refers to the way, manner, or to what degree something was done; it replaces adverbs or adverb phrases. If the verb contains a modal, a form of the verb “be” or a form of the helping verb “have,” the subject and predicate are reversed:

“Mary is very beautiful.”
“How beautiful is Mary?”

The do formation is used when the verb is not a modal, a form of the verb “be” or a form of the helping verb “have,”:
“John ran quickly to school”
“How did John run to school?”

Like “why,” “how” sometimes does not replace a specific word or phrase but asks for the way in which something was accomplished. The clause in the sentence explaining “how” is usually introduced with “by”:

“Bill passed the test by studying hard.”
“How did Bill pass the test?”

“Where” refers to adverbials of place or location. If the verb contains no modal, form of the verb “be” or form of the helping verb “have,” then the subject and predicate are switched.

“The keys are on the table.”
“Where are the keys?”