(책) 교보문고 : https://product.kyobobook.co.kr/detail/S0000031031851. Unit 1 ~ Unit 6https://youtu.be/aE10nN6SXu4?si=H30wOuYiCj3rHvzf 2. Unit 7 ~ Unit 12https://youtu.be/Ja9q6QMYXz4?si=W4MqDT1jsXnC9z07 3. Unit 13 ~ Unit 18https://youtu.be/hmehGpqb0bY?si=Ox5b_qOkDLx4py1P 4. Unit 19 ~ Unit 25https://youtu.be/QUR8J4fLNyg?si=RznWAp2Smlo5Qp_V 5. Unit 26 ~ Unit 31https://youtu.be/yROasA4TP7k?si=qsNpJ5sOsN..
