原标题:2015年考研英语一真题答案（无缺版）
section 1 use of english

　　directions:

　　read the following text. choose the best word(s) for each numbered blank and mark [a], [b], [c] or [d] on answer sheet 1. (10 points)

　　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 1932 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 in olfactory genes is difficult to explain, for now. 10 perhaps, as the team suggests, it draws us to similar environments but there is more 11 it. there could be many mechanisms working in tandem that 12 us in choosing genetically similar friends 13 than “functional kinship” of being friends with 14 !one of the remarkable findings of the study was that the similar genes seem to be evolving 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 corroborate people’s 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. the team also controlled the data to check ancestry of subjects.

　　section ii reading comprehension??

　　1、what

　　2、concluded

　　3、on

　　4、compared

　　5、samples

　　6、

insignificant

　　7、know

　　8、resemble

　　9、also

　　10、perhaps

　　11、to

　　12、drive

　　13、ratherthan

　　14、benefits

　　15、faster

　　16、understand

　　17、contributory

　　18、tendency

　　19、ethnic

　　20、see