ride a bike造句

He can't maintain enough equilibrium to ride a bike.
他骑自行车不能保持平衡.

He can ride a bike now, but he couldn't a few weeks ago.
他现在能骑自行车了, 但几星期前他不会.

Because I was old enough to ride a bike after I went to junior middle school.
因为进了高中我年龄大了,可以骑车.