– Would you mind turning down the music?– .
A:Yes, I would
B:No, of course
C:No, not at all
如图所示,一块橡皮用细线悬挂于O点,用铅笔靠着线的左侧水平向右匀速移动,运动中始终保持悬线竖直,则橡皮运动的速度( )
如图,正方形ABCD的边长为9.将正方形折叠.使顶点D落在BC边上的点E处,折痕为GH.若BE:EC=2:1,则线段CH的长是( )
三北防护林最重要的生态效益是( )
My mother will go to Beijing _____.