2015考研英语完形

though not biologically related， friends are as “related” as fourth cousins， sharing about 1% of genes. that is _（1）_a study， published from the university of california and yale university in the proceedings of the national academy of sciences， has__（2）__. the study is a genome-wide analysis conducted __（3）__1， 932 unique subjects which __（4）__pairs of unrelated friends and unrelated strangers. the same people were used in both_（5）__. while 1% may seem_（6）_， it is not so to a geneticist. as james fowler， professor of medical genetics at uc san diego， says， “most people do not even _（7）_their fourth cousins but somehow manage to select as friends the people who_（8）_our kin.”the study_（9）_found that the genes for smell were something shared in friends but not genes for immunity .why this similarity exists in smell genes is difficult to explain， for now， _（10）_， as the team suggests， it draws us to similar environments but there is more_（11）_it. there could be many mechanisms working together that _（12）_us in choosing genetically similar friends_（13）_“functional kinship” of being friends with_（14）_！
one of the remarkable findings of the study was the similar genes seem to be evolution_（15）_than other genes studying this could help_（16）_why human evolution picked pace in the last 30， 000 years， with social environment being a major_（17）_factor. the findings do not simply explain peoples_（18）_to befriend those of similar_（19）_backgrounds， say the researchers. though all the subjects were drawn from a population of european extraction， care was taken to_（20）_that all subjects， friends and strangers， were taken from the same population.
1. [a] when [b] why [c] how [d] what
2. [a] defended [b] concluded [c] withdrawn [d] advised
3. [a] for [b] with [c] on [d] by
4. [a] compared [b] sought [c] separated [d] connected
5. [a] tests [b] objects [c]samples [d] examples
6. [a] insignificant [b] unexpected [c]unbelievable [d] incredible



7. [a] visit [b] miss [c] seek [d] know
8. [a] resemble [b] influence [c] favor [d] surpass
9. [a] again [b] also [c] instead [d] thus
10. [a] meanwhile [b] furthermore [c] likewise [d] perhaps
11. [a] about [b] to [c]from [d]like
12. [a] drive [b] observe [c] confuse [d]limit
13. [a] according to [b] rather than [c] regardless of [d] along with
14. [a] chances [b]responses [c]missions [d]benefits
15. [a] later [b]slower [c] faster [d] earlier
16. [a]forecast [b]remember [c]understand [d]express
17. [a] unpredictable [b]contributory [c] controllable [d] disruptive
18. [a] endeavor [b]decision [c]arrangement [d] tendency
19. [a] political [b] religious [c] ethnic [d] economic
20. [a] see [b] show [c] prove [d] tell
【参考答案】dbcac　adabd　babdc　cbdca