Academic writing is always considered to be purely objective, impersonal and informational, designed to disguise the author and deal directly with facts. This objectivity in academic writing, however, has been challenged by researchers (Biber, 2006; Charles, 2006; Hunston, 1994, 2004; Hyland, 2000 & 2002; Hyland and Tse, 2004), because academic writing is obviously persuasive in presenting its propositional information. The arguments in academic discourse are rarely made without interpretive statements and assessments of their likely probability. These assessments necessarily involve personal or subjective judgments in order to make the discourse persuasive, which is typically proved in research abstracts.