OEC L4: I'm sick 生病了OEC Level 4 Student's Book 7: I'm sick Oxford Elementary Chinese (OEC) is a four level series, designed for young learners of Chinese. Using a communicative approach based on engaging stories and activities, the series enables learners to build strong listening and speaking skills. It also helps them develop an interest in reading, writing and different cultures. * *Please note that the pictures on the inner pages of the sample book are for style