| In the end, the open-field system of crop rotation was an obstacle to increased agricultural productivity. |
| In springtime, the tule marshes trapped floodwaters, and for miners and early travelers they were yet another obstacle to movement. |
| To the British, that unsubjugated savage kingdom constituted an intolerable obstacle to progress. |
| Entrenched management attitudes can be an enormous obstacle to facility projects that can reduce costs. |
| It would prove an insurmountable or even lethal obstacle to most cracksmen. |
| A bigger obstacle to hurling progress is the number of players unwilling to commit to the cause. |
