I don't think you have __________ the work on time.
A:difficulty finishing
B:difficulties to finish
C:difficulty to finish
D:a difficulty finishing
如图,在平行四边形ABCD中,E是AB的中点,CE和BD交于点O,设△OCD的面积为m,△OEB的面积为5,则下列结论中正确的是( )
使用天平测量物体的质量,下列说法错误的是 ( )
若直线x+2y+1=0与直线ax+y﹣2=0互相垂直,那么a的值等于( )