Cultivating EFL learners' critical thinking ability is an urgent task for English teachers. To integrate the training of language skills and cultivation of critical thinking ability into one language course, the author designed an activity called simplified Modal United Nations conference, which is based on the revised Bloom's Taxonomy that classifies thinking as containing six cognitive levels of complexity. This activity would help learners to develop higher-level cognitive abilities such as abilities of analyzing, evaluating and creating, while enhancing their language competence by directing their attention to language forms.