1. The document discusses four models of second language learning: the Good Language Learners model, Monitor Theory, Brown and Fraser's model, and Levin's model. 2. The Good Language Learners model identifies teaching, learner, and context as three independent variables that directly link to the dependent variables of learning and outcome. However, it remains unclear which sub-variables affect learning. 3. Monitor Theory and Brown and Fraser's model are also discussed but no details are provided.