A:Seating; wa
B:Seated; were
C:Sitting; wa
D:Sat; were
已知点P在直线P1P2上,且P1P→=25PP2→,若P1,P2,P的坐标分别为(x,﹣4,3),(﹣2,y,1),(3,0,z),求x,y,z.
非洲大陆的地形主要是( )
对开普勒行星绕太阳运转的第三定律 r3T2 =k,正确的是( )