名著阅读题。
It there anyone in your class ______ family is in the country?
已知ΔABC中,∠A∶∠B∶∠C=3∶7∶8,则ΔABC的形状是( )
设函数fx=x2-6x+c1x2-6x+c2x2-6x+c3,集合M=x|{f(x)=0}={x1,x2,x3,x4,x5}⊆N*,设c1≥c2≥c3,则c1-c3等于( )