Throughout the process of syntactic development, children acquire and develop question structures. According to O'Grady and Cho (2011), at the early stages of language acquisition, children ask yes-no questions by rising intonation alone as they develop awareness to auxiliary verbs only at a later stage. When auxiliary verbs make their appearance, it takes children a few months before they are able to use inversion in yes-no questions. The development of WH- questions occurs between the ages of two and four, when children acquire auxiliary verbs that then leads to the ability to use inversion in questions. However, some children find inversion easier in yes-no questions than in WH- questions, since the position of the WH- word and the auxiliary verb both must changed (e.g., "You are going where?" instead of "Where are you going?").