问题
My American friend Sam is interested in Yangzhou very much. He wonders _______.
A:that Yangzhou was very rich in the ancient times
B:who built Ge Garden and He Garden
C:when was the Wenchang Pavilion built
D:what is the City Flower of Yangzhou
B:who built Ge Garden and He Garden
C:when was the Wenchang Pavilion built
D:what is the City Flower of Yangzhou
正确答案是：
