In this paper, I will argue that in teaching L2, it is important to take a holistic teaching method considering various learning styles of the learners and the nature of L2 learning. Under the situation that most of the school education is centered on the left brain activity, learners with the right brain preference tend to get only to the lower proficiency than they really can. To prove this, I conducted a experiment on two classes of high school students. I decided the hemispheric preference of each students using HMI (hemispheric mode indicator) Then I compared the hemispheric preferences of students with their scores in English tests. The students with right hemispheric preference show significantly lower scores than the ones with left preference. It is implied that the current English education should adapted to address various learning and cognitive styles and whole-brain L2 teaching method should replace the left-centered instruction in the learning environment.