The Battle of Grand Gulf was fought on April 29, 1863, during th: Both yes–no questions and wh-questions in English are mostly formed using subject–auxiliary inversion (Am I going tomorrow?, Where can we eat?), which may require do-support (Do you like her?, Where did he go?). In most cases, interrogative words (wh-words; e.g. what, who, where, when, why, how) appear in a fronted position. For example, in the question What did you see?, the word what appears as the first constituent despite being the grammatical object of the sentence. (When the wh-word is the subject or forms part of the subject, no inversion occurs: Who saw the cat?.) Prepositional phrases can also be fronted when they are the question's theme, e.g. To whose house did you go last night?. The personal interrogative pronoun who is the only interrogative pronoun to still show inflection for case, with the variant whom serving as the objective case form, although this form may be going out of use in many contexts.[218]