1. A popular explanation of play has been that it helps juveniles develop the skills they will need to hunt. (test2 passage 3)

　　分析：本句的主句为“A popular explanation of play has been that…”;“that it helps juveniles develop the skills they will need to hunt”为that引导的表语从句，作has been的表语;“they will need to hunt”为定语从句，关系词在定语从句中作宾语，被省略。

　　2. Comparing measurements for fifteen orders of mammal, he and his team found larger brains (for a given body size) are linked to greater playfulness. (test2 passage 3)

　　分析：本句的主句为“he and his team found larger brains (for a given body size) are linked to greater playfulness”;“Comparing measurements for fifteen orders of mammal”为现在分词短语作状语;“larger brains (for a given body size) are linked to greater playfulness”为宾语从句，that被省略。

　　3. If you plot the amount of time a juvenile devotes to play each day over the course of its development, you discover a pattern typically associated with a ‘sensitive period’—a brief development window during which the brain can actually be modified in ways that are not possible earlier or later in life. (test2 passage 3)

　　分析：本句较长，主句为“you discover a pattern”;“If you plot the amount of time”为if引导的本句的条件状语从句;“a juvenile devotes to play each day over the course of its development”为定语从句，作time的定语，关系词在定语从句中作宾语，被省略;“associated with a ‘sensitive period’”为过去分词短语作定语;“during which the brain can actually be modified”为which引导的定语从句，作window的定语从句;“that are not possible earlier or later in life”为定语从句，作ways的定语，关系词为that。

　　4. These fracture zones, where the collisions occur, are where earthquakes happen. (test3 passage 2)

　　分析：本句的主句为“These fracture zones are where earthquakes happen”;“where the collisions occur”为定语从句，作zones的定语，关系词为where;“where earthquakes happen”为where引导的表语从句。

　　5. When studying their mother tongue, linguists act as their own informants, judging the ambiguity, acceptability, or other properties of utterances against their own intuitions. (test3 passage 3)

　　分析：本句的主句为“linguists act as their own informants”, “When studying their mother tongue”为when引导的现在分词短语做时间状语;“judging the ambiguity, acceptability, or other properties of utterances against their own intuitions.”为现在分词短语做伴随状语，引导词省略。

　　6. People talk abnormally when they know they are being recorded, and sound quality can be poor. (test3 passage 3)

　　分析：本句为and连接的一个并列句“People talk abnormally”和“sound quality can be poor”并列;“when they know they are being recorded”为when引导的时间状语从句;“they are being recorded”为宾语从句，做know的宾语，引导词that省略。

　　7. Linguists also make great use of structured sessions, in which they systematically ask their informants for utterances that describe certain actions, objects or behaviors. (test3 passage 3)