— How is it going?
— It's ________. The weather here is very beautiful and I don't want to go home.
在△ABC中,a,b,c分别为内角A,B,C的对边,3cosA﹣cos(B+C)=1,a=15,B=π4,则b等于( )
女性卵细胞中所含的性染色体是( )