Vocabulary in Use Intermediate: 100 Units of Vocabulary Practice in North American English 外国语言
A Michigan Guide: Step Up to the TOEFL iBT for Intermediate Students: Developing Essential Skills [With CD (Audio)]
Forces of Nature, Earthquakes: A Reading Skills Text 普通语言学
Step Up to the TOEFL(R) Ibt for Students at the Basic Level (with Audio CD): A Michigan Guide