Because of the snow many parts of the countryside are only by helicopter.A. potentialB.

问题补充：

Because of the snow , many parts of the countryside are only by helicopter.

A. potential

B. productive

C. accessible

D. visual

答案：

A. potential

B. productive

(答案→)C. accessible

D. visual

解析：考查词义辨析。potential 有潜力的，productive 多产的，accessible 可接近的，visual 视觉的，句意：由于大雪，乡下的许多部分只有靠直升飞机可以接近。所以选C。