9.Among the most popular : paternity and kinship testing , which adopted children can use to find their biological relatives and families can use to track down kids put up for adoption.

【分析】復合句。句子的主干是Among the most popular : paternity and kinship testing...。因主句省略了謂語動詞，此處冒號相當于be動詞are。Which引導定語從句，先行詞是paternity and kinship testing。定語從句本身又是由and連接的并列句，which在定語從句中作兩個use的賓語，put up for adoption是過去分詞短語作kids的定語。

【譯文】在基因檢測中，最受歡迎的是父子血緣關系測試——被收養的孩子可以利用這個測試找到自己生物學上的親戚，家庭也可以用此來追查被受養孩子的下落。

【點撥】1）track down 意思是“跟蹤找到，追查到”。2）put up for adoption指“將···送給別人收養”。

【臨摹】多年來我一直在打聽一些老朋友的下落。

10.This DNA can reveal genetic information about only one or two ancestors , even though , for example , just three generations back people also have six other great-grand-parents or , four generation back , 14 other great-great-grandparents .

【分析】復合句。句子的主干為This DNA can reveal genetic information... 。Even though引導讓步狀語從句，從句由or連接的兩個并列分句構成。并列結構中的同等句子成分省略。

【譯文】舉例來說，只要上溯三代，一個人就會有八個曾祖父母，或者上溯四代，就會有十六個曾曾祖父母，即便如此，這種DNA只能揭示一到兩位祖先的基因信息。

臨摹答案

2.The sudden noise from the next room interrupted my trains of thought.

3.The more learned a man is , the more modest he usually is .

4.Many primary schools shut down early for the vacation for fear of the advent of earthquake.

6.He will break school rules if he goes on playing truant .

7.It is William who is not very cheerful and thus needs s holiday to pull himself together.

9.I’ve been trying to track down some old friends over the years .