The present study aims at investigating problems with a TEE class in terms of classroom activities and code-switching. One middle school teacher and her students participated in the study. The teacher taught a writing class in TEE context. She taught more than half of the class in English. Her students experienced different interactional patterns in four different activities. However, most of the students could not participate both in pair work and group work without her teacher’s help. That was because the teacher had problems with giving instructions: (1) her instructions about the activities were not clear enough; (2) she did not provide any modelling for the activities; and (3) she did not check any clarifications for the activities. Also, the ratio of the teacher’s utterance to students’ was too high: 96% in English and 89.5% in Korean. In addition, she did not use any pause in code-switching from English to Korean, deprived of checking whether her students understood the target language input given in English. Directions for further research and pedagogical implications will be discussed.