下列结构中,与长骨骨折后的修复密切相关的是( )
A:骨膜
B:骨髓
C:骨松质
D:骨密质
They are going to Dalian _________ a school trip in the summer holiday.
(3x+2)(﹣x4+3x5)+(3x+2)(﹣2x4+x5)+(x+1)(3x4﹣4x5)与下列哪一个式子相同( )
在平面直角坐标系xoy中,圆C的方程为x2+y2-8x+15=0,若直线y=kx-2上至少存在一点,使得以该点为圆心,1为半径的圆与圆C有公共点,则k的最大值为