Passage 1

16. What are scientists trying to explain according to the passage?
答案：(A) How being an identical twin influences one’s identify.
【点评】：细节题。本篇文章开头即指出 ‘they(scientists) are trying to explain how being half of the biological pair influences a twin’s identity.’由此可知科学家一直试图想要解释双胞胎的身份人格是如何受到影响的。

17. What do we learn about the twin Jims?
答案：(B) They grew up in different surroundings.
【点评】：细节题。关键词即是Jim 这个名字。关于两个Jim的情况是：他们一直生长在不同家庭，直到39岁才见面。‘… grew up in different families and did not meet for 39 years.’ 他们都结过两次婚，第二次婚姻中，妻子都叫贝蒂。‘Both men were married twice… and their second wives were both named Betty.’ 而他们的第一个孩子都是儿子 ‘Both twins named their first sons James Allen.’

18. Why are scientists interested in studying identical twins raised in different families?
答案：(A) They want to find out the relationship between environment and biology.
【点评】：细节题。通过对两个Jim的研究， These twins help scientists understand the connection between environment and biology。