small wheel

例句：

1. 1. The carhas a small wheel on the front.
   这辆车前部有一个小轮子。
2. 2. Thetrain has a small wheel at the endof the track.
   火车在轨道的末端有一个小轮子。
3. 3. The bike has asmall wheel at the back.
   自行车在后部有一个小轮子。