After we walked the forest and a river we arrived at that small village.A. across; ac

问题补充：

After we walked the forest, and a river, we arrived at that small village.

A. across; across

B. through; across

C. across; through

D. through; through

答案：

A. across; across

(答案→)B. through; across

C. across; through

D. through; through

解析：穿过两边有高度的地方用介词through；穿过广阔的海洋，沙漠，平原用across。