Temporal in-adverbials (TIAs) are a class of English expressions that can be exemplified with in three days. They are remarkable in that, depending on the syntactic position they occupy, TIAs are subject to very different distributional constraints. In some configurations, their licensing is conditioned by the lexical aspect of verbal predicates. In others, these expressions are negative polarity items. Though both varieties of TIAs have been discussed extensively in the semantics literature (Gajewski, 2005, 2007; Hoeksema, 2006; Iatridou and Zeijlstra, 2017, 2021; Krifka, 1989, 1998), no attempt has been made to understand the relationship between the two. I offer a unified semantic analysis of TIAs, which derives from semantic principles their eclectic distributional constraints.