问题描述：
今天在英国和美国的亚马逊网站上看到了剑桥雅思8的官方预售版本,但是上面有三个版本：
①Cambridge IELTS 8 Student's Book with Answers,$15.52,Mar.31,2011
②Cambridge IELTS 8 Audio CDs (2),$44.00,Mar.31,2011
③Cambridge IELTS 8 Self-study Pack (Student's Book with Answers and Audio CDs (2)),$54.00,Apr.30,2011
请问这三者究竟有什么区别,该买哪一个?
①Cambridge IELTS 8 Student's Book with Answers,$15.52,Mar.31,2011
②Cambridge IELTS 8 Audio CDs (2),$44.00,Mar.31,2011
③Cambridge IELTS 8 Self-study Pack (Student's Book with Answers and Audio CDs (2)),$54.00,Apr.30,2011
请问这三者究竟有什么区别,该买哪一个?
问题解答：
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