I saw a lighthouse at the mouth of the river.
A. locating
B. location
C. located
D. which located
网友回答
A. locating
B. location
(答案→)C. located
D. which located
解析：考查分词做宾语补足语，句意：我看见一个灯塔在河口处。Be located at/in…位于…,see +宾语+宾语补足语，a lighthouse和locate是被动关系，用过去分词做宾语补足语。选C。