- _____you sing English songs yesterday?
- No,I didn't. ( )
A:Do
B:Did
C:Will
如图所示的各种现象中,物体运动状态没有改变的是( )
—I don't want to do as ____sports as Tony does.—But you have to do if you want to be as _____as he.
已知椭圆的参数方程为x=cosφy=2sinφ(φ为参数),点M在椭圆上,点O为原点,则当Φ=π3时,OM的斜率为( )