简介:【句型剖析】1.【原句再现】Johnwasstudyinginhisroomwhenheheardscreaming.约翰正在房间里做功课时,突然听到了尖叫声。【考点剖析】when在此句中意为“这时,突然”,相当于atthis/thattime,常用于以下结构中:bedoing…when…正在做……这时……;beabouttodo…when…正打算做……这时……;beiustgoingtodo…when…正要……这时……;hadiustdone…when…刚做了……这时……;beonthepointofdoing.…when…正要……这时……
简介:ForagraphG,P(G,λ)denotesthechromaticpolynomialofG.TwographsGandHaresaidtobechromaticallyequivalent,denotedbyG-H,ifP(G,λ)=p(H,λ).Let[G]={H|H-G}.If[G]={G},thenGissaidtobechromaticallyunique.Foracomplete5-partitegraphGwith5nvertices,defineθ(G)=(a(G,6)-2^n+1-2^n-1+5)/2n-2,wherea(G,6)denotesthenumberof6-independentpartitionsofG.Inthispaper,theauthorsshowthatθ(G)≥0anddetermineallgraphswithθ(G)=0,1,2,5/2,7/2,4,17/4.Byusingtheseresultsthechromaticityof5-partitegraphsoftheformG-Swithθ(G)=0,1,2,5/2,7/2,4,17/4isinvestigated,whereSisasetofedgesofG.Manynewchromaticallyunique5-partitegraphsareobtained.