Language teacher plays an important role in classroom setting. Teacher provides plenty of input and teaches target language knowledge to learner. Meanwhile, teacher promotes opportunity of real language use for learner to practice. The more chances learner speaks and uses the target language, the more comfortable and confident the learner will become. During the teaching and learning process, teacher provides appropriate challenge to learner. This could push the learner’s output production to a maximum. Teacher should be sensitive to learner’s reaction to the teaching strategy and adjusts task according to the circumstance. Always making sure learner manages the task correctly and the language acquisition is carried out. It is crucial that teacher gives learner encouragement as much as he/she can. Positive feedback in learner’s achievement can increase learner’s motivation in language study. Teacher should give learner error correction on time, provide appropriate help when learner needs and teach form of target language to facilitate learner’s language acquisition.