4)The explanation for the matter( decrease/rise / change/ ph enomenon)of .. involves many (different/complicated/puzzlin gfactors(reasons/ aspects 例句 The explanation for the phenomenon of the rising teenage suicide rate involves many complicated factors. Some attribu te the rise to an overemphasis on early success others po int to mounting peer pressure, and still others to confusion over changing social values 5)The reasons for ...are many but for the most part center on (concentrate on /focus on) 例句: The reasons for the phenomenon of the rising teenage suici de rate involves many complicated factors. some attribute t he rise to an overemphasis on early success, others point to mounting peer pressure, and still others to confusion ov er changing social values 6There are several causes for this significant growth first second finally 7We have reason to believe that 8This can be expressed as follows4) The explanation for the matter(decrease/rise /change/ ph enomenon) of …….involves many (different/complicated/puzzlin g)factors(reasons/aspects) 例句： The explanation for the phenomenon of the rising teenage suicide rate involves many complicated factors. Some attribu te the rise to an overemphasis on early success, others po int to mounting peer pressure, and still others to confusion over changing social values. 5) The reasons for ……….are many, but for the most part center on (concentrate on /focus on)…….. 例句： The reasons for the phenomenon of the rising teenage suici de rate involves many complicated factors. Some attribute t he rise to an overemphasis on early success, others point to mounting peer pressure, and still others to confusion ov er changing social values. 6)There are several causes for this significant growth in ………, first……….second…………finally………… 7)We have reason to believe that …………. 8)This can be expressed as follows: