The grammar of Interlingua is based largely on that of the Romance languages, but simplified, primarily under the influence of English. However, all of the control languages, including German and Russian, were consulted in developing the grammar. Grammatical features absent from any of the primary control languages (English, French, Italian, Spanish and Portuguese) were dropped. For example, there is neither adjectival agreement (Spanish/Portuguese "gatos negros" 'black cats'), since this feature is absent in English, nor continuous verb tenses (English "I am reading"), since they are absent in French. Conversely, Interlingua has articles, unlike Russian, as Russian is a secondary control language.