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W(xu)W(wng) > иԇ > 俼иxҪcęC

俼иxҪcęC

l(f)rg:2017-06-29݋f

иx俼^У]һc“ęC”Dzе!҂xY}}ȷ涼ҪзмɵMС@“ęCgirl”o]Ďc“ęCؼ”ȡиx߷

ęCһ俼(jng)ҪW(xu)Yx{(dio)

F(xin)ڸW(wng)վx俼(jng)ͼкܶ࣬@Щ(ni)݌҂Ă俼ЎǴҪW(xu)YxҪһEҪW(xu)(j)ԼČHrM{(dio){(dio)֮ǰһҪMģ֪Լˮƽ~RZwϵLyֻг˽ԼĆ}cᘌԵĽb俼(jng)ԼĂ俼|(zh)

ęC俼YJ(rn)(zhn)TPO

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ęC}һԭĞ(j)

иx}һ֌W(xu)ǐ뮔(dng)ȻԼ˼SʽMx@xĴ𰸺ܶr¶e`Сһһ}Ŀ

According to paragraph 4, what aspect of extinction episodes does the companion-star hypothesis supposedly clarify?

A. Their location

B. Their frequency

C. Their duration

D. Their severity

companion star hypothesisP(gun)I~λһThe possibility that mass extinctions may recur periodically has given rise to such hypotheses as that of a companion star with a long-period orbit deflecting other bodies from their normal orbits, making some of them fall to Earth as meteors and causing widespread devastation upon impact.fmass extinctionķ(f)l(f)֧companion star hypothesis@hypothesisf܉׃Ό(do)һЩwƫx܉ɞEǵԭfҴΰl(f)܉extinctionlʣB}һҪԭĞ}ȡиx߷

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