The church tower on the top of the cliff has been a _________for

The church tower on the top of the cliff has been a _________for sailors, （land, mark）
【正确答案】：landmark
【题目解析】：原句的意思是“山崖上的教堂塔楼一直是水手们的坐标”。因此这里需要填的是个名词，我们填landmark。