A:③②⑥⑤①④
B:④②①⑤⑥③
C:②⑥⑤①④③
D:③①⑤②⑥④
如图所示,一个球绕中心轴线OO′以角速度ω做匀速圆周运动,则( )
— ______ does he get to school?— He rides his bike.
The Red Army soldiers had to fight ________ all kinds of difficulties in their fight ________ the people's freedom.