6. Environmental education offers an arena in which these skills can be developed, which is essential for these children as future decision-makers. (test1 passage 1)
分析：本句主句为“Environmental education offers an arena”;“in which these skills can be developed”为which引导的定语从句，作arena的定语;“which is essential for these children as future decision-makers”为which引导的非限制性定语从句。
7. Eye position in freshwater dolphins, which often swim on their side or upside down while feeding, suggests that what vision they have is stereoscopic forward and downward. (test1 passage 2)
分析：本句的主句为“Eye position in freshwater dolphins suggests that…”;“which often swim on their side or upside down”为which引导的定语从句，作freshwater dolphins的定语;“while feeding”为while引导的状语，分词短语作状语;“that what vision they have is stereoscopic forward and downward.”为that引导的宾语从句，作suggest的宾语;“what vision they have”为what引导的主语从句，作is的主语。
8. And although preliminary experimental evidence suggests that their in-air vision is poor, the accuracy with which dolphins leap high to take small fish out of a trainer's hand provides anecdotal evidence to the contrary. (test1 passage 2)
分析：本句主句为“the accuracy provides anecdotal evidence to the contrary”;“although preliminary experimental evidence suggests that their in-air vision is poor”为although引导的让步状语;“that their in-air vision is poor”为that引导的宾语从句，作suggest的宾语;“which dolphins leap high to take small fish out of a trainer's hand”为which引导的宾语从句，作with的宾语从句;“to take small fish out of a trainer's hand”为不定式作目的状语。
9. But a written form is essential for this, so the mere possibility of revival has led many speakers of endangered languages to develop systems of writing where none existed before. (test2 passage 1)
分析：本句中用so(连词)连接“a written form is essential for this”和“the mere possibility of revival has led many speakers of endangered languages to develop systems of writing where none existed before”两个简单句成为一个并列句;“where none existed before”为where引导的地点状语从句。
10. One factor which may help to ensure that some endangered languages do not die out completely is people's increasing appreciation of their cultural identity. (test2 passage 1)
分析：本句主句为“One factor is people's increasing appreciation of their cultural identity”;“which may help to ensure that some endangered languages do not die out completely”为which引导的定语从句，作factor的定语;“that some endangered languages do not die out completely”为that引导的宾语从句，作ensure的宾语。
