Task: Translation
Input (English): English sentence: Doob built on work by Paul Lévy and, during the 1940's and 1950's, he developed basic martingale theory and many of its applications.
Output (Tagalog): Doob nakapaloob sa trabaho sa pamamagitan ng Paul magpataw ng buwis at, sa panahon ng 1940's at 1950's, siya ay binuo basic matingeil teorya at marami ng kanyang aplikasyon.