Tense is a grammatical category by means of which some natural languages express the temporal location of the event described by the sentence in which the grammatical tense occurs. (This definition assumes a distinction between grammatical and lexical categories. For the technically inclined, lexical categories are part of the lexicon of a language and are open classes [classes that allow new vocabulary through compounding, derivation, coining, and borrowing]. They become inflected, and do not contract, affix, or cliticize. Examples of lexical categories are nouns, adjectives, adverbs, verbs. Grammatical categories are part of the grammatical system of a language and are closed classes [classes that do not allow additions]. They may contract, affix, or cliticize. Examples include inflectional and derivational morphemes and function words, such as prepositions, determiners, conjunctions, and pronouns.) An instance of a tensed language is English. In the English unembedded sentence "Bill called," the grammatical tense...