Viewpoint is a two-level series in American English for adults and young adults taking learners from a high intermediate to advanced level of proficiency (CEFR B2 ? C1). Viewpoint is an innovative course that’s based on extensive research into the Cambridge English Corpus taking students to a higher level of proficiency to become effective communicators. 英語 教科書 学校 教材 勉強 参考書 ネイティブ おすすめ テキスト text Cambridge