the Atlantic Ocean crosses the equator the trade winds cause a flow of water to the west

问题补充：

the Atlantic Ocean crosses the equator, the trade winds cause a flow of water to the west.

A. That

B. When

C. Where

D. Though

答案：

A. That

B. When

(答案→)C. Where

D. Though

解析：从句子结构上判断，前一分句属于状语从句，从句子意义上判断，该分句应为地点状语，故答案应为C项。