stumbler

例句：

1. 1. The old road was a stumbling block for the new construction project.
   这条老路是新建设项目的绊脚石。
2. 2. The hiker stumbled over a rock and fell to the ground.
   登山者绊倒在一块石头上摔倒在地。
3. 3.The accident happened when he stumbled while walking down the stairs.
   事故发生在他下楼时绊倒了。