The present study aims to investigate the appearance of the English passive progressives and to understand how and why these constructions appear in the English language. Visser (1963-73) prefers to see the main reason for the appearance of the English passive progressive constructions as the “urge, permanently inherent in English as an analytic language, to signal separately every separate shade of meaning, function or connotation”. If we develop Visser’s idea and observe the change of the English verbal phrases, we find a direction of change concerning the English passive progressive as found by Traugott (1965; 1972). As language changes from Proto-Indo-European to Germanic to West-Germanic to English, the full inflections of Proto-Indo-European concerning the verb phrases are lost. English, an analytic language rather than a synthetic one, has changed to fill the systematic gap with periphrastic verb phrases instead of inflections. This process of maximizing the sequences of auxiliaries may be called the Principle of Maximizing the Sequences of Auxiliaries or the Principle of Filling the Systematic Gap left by Proto-Indo-European as a result of the loss of full inflections.