A clean environment can help the city bid for the Olympics, which will promote its economic development.
A. in nature
B. in return
C. in turn
D. in fact
网友回答
A. in nature
B. in return
(答案→)C. in turn
D. in fact
解析：考查介词短语：A. in nature在自然中 B. in return做为回报 C. in turn依次，轮流，反之，D. in fact事实上，句意：一个清洁的环境可以帮助申办奥运会，这反过来又会促进经济发展。选C。