教练告诉骑手要收紧缰绳控制马匹的速度。

The instructor told the rider to ___rein in the horse to slow down.

她紧紧握住缰绳，引导马匹转向。

She held the ___reins tightly to guide the horse to turn.

公司给了她充分的自由来设计这个项目。

The company gave her full ___rein to design the project.