there were too many stones on the roads the soldiers (战士) walked to Lushan County in Ya’

问题补充：

there were too many stones on the roads, the soldiers (战士) walked to Lushan County in Ya’an Earthquake.

A. If

B. And

C. So

D. Although

答案：

A. If

B. And

C. So

(答案→)D. Although

解析：句意：尽管路上有太多的石头，战士们在雅安地震中步行到庐山县。too many +可数名词的复数；

If如果，and和，so所以，although尽管，即使。根据句意故选D。