When he was in America he went on a journey to see Yellow Stone Park.A. in factB. by cha

问题补充：

When he was in America, he went on a journey to see Yellow Stone Park.

A. in fact

B. by chance

C. in turn

D. on purpose

答案：

A. in fact

B. by chance

C. in turn

(答案→)D. on purpose

解析：考查介词短语。A事实上；B偶然；C依次；D故意地，有意的；句意：当他在美国的时候，他有意去看了黄石国家公园。故D正确。