This book presents a model for describing translation performance as a basis for contrastive linguistics, in the realm of tense and aspect. It is based on extensive corpus studies investigating the differences between English and Portuguese using authentic translations in the two directions. In method and substance, the book features several original claims, trying to achieve a balance between theoretical issues and the presentation of concrete translation data. In addition, it deals with computational applications of parallel corpora. Translation-based corpus studies should thus be appropriate for translator education, and for introducing contrastive semantics and the methodology of corpus linguistics to students of linguistics and computer science. Researchers in tense and aspect, translation, and corpus linguistics are, nevertheless, the book’s primary audience.