问题补充：
Which of the following is in the USA?
A. The Big Ben.
B. The Great Wall.
C. The Leaning Tower of Pisa.
D. The Golden Gate Bridge.
答案：
A. The Big Ben.
B. The Great Wall.
C. The Leaning Tower of Pisa.
(答案→)D. The Golden Gate Bridge.
解析：The Big Ben.英国大本钟；The Great Wall.中国长城；The Leaning Tower of Pisa.意大利比萨斜塔；The Golden Gate Bridge.美国金门大桥。根据常识可知金门大桥在美国，故选D。
