With input, the focus should be on the student and the extent to which he understands (Gass et al 1994). Researchers admit that nonuse takes place when the information contained in the input is included into a learner's grammar. However, the fact that the information is already included into a grammar does not necessarily exclude it from being utilized--although it may be used in a different way from what one normally thinks of. When the information contained in the input is already a part of one's knowledge base, the additional input might be used for rule strengthening or hypothesis reconfirmation. Part of becoming a fluent speaker of a second language involves the automatic retrieval of information from one's knowledge base. The knowledge base is developed through practice or repeated exposure to exemplars. Thus, information that may appear redundant may be serving an important purpose in terms of the access the learner has to that information (Jonassen and Hannum 1998).
2. Feedback is important technique in learning because it helps a student to understand his mistakes and correct them at once. Feedback should be supported by events such as motivating students, communicating the learning objectives, directing students' attention, activating related knowledge, providing guidance, promoting transfer (generalization), eliciting performance, and providing feedback. The teachers' statements, which are spontaneous and oral, are more difficult to categorize than the written statements of the authors. The content and grammar of the teachers' statements were less structured and precise than those of the authors. On-going, specific and immediate feedback helps teachers to save time and direct learning process. Feedback encourages students to uimprove. Several analogies constructed for the same concept can help the students view the target concept from different perspectives. The analogies function like conceptual lenses, with each one bringing different features of the concept into sharper focus (Kitajima and Polson 1997). Teachers also are encouraged to use the model to construct additional analogies to complement an author's analogy. Several analogies constructed for the same concept can help the students view the target concept from different perspectives. The analogies function like conceptual lenses, with each one bringing different features of the concept into sharper focus. During normal or stable times, scientific activities turn to the refinement of established knowledge claims. But the review of historical documents and actual practice of scientists revealed that there are also times when members of a scientific community are in disagreement about what are the appropriate background knowledge and critical problems that should guide the design of investigations and the evaluation of evidence and knowledge claims (Gass et al 1994).
3. Taken together, instructional steps are a direct outcome of teacher assessment decisions that begin to alter the dynamics of the classroom learning environment. The public expression of what matters and what is valued begins to change. As students learn the criteria, they not only learn the rules of the game in the classroom, they also learn what is valued in the scientific discipline (Manouchehri 2001). Other models include having students work in pairs or small groups to come to a consensus view through