A man walks past an architecture model during the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yao Jianfeng)

People view an architecture load-bearing system during the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yao Jianfeng)

People visit an energy-saving cabin during the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yao Jianfeng)

A man visits an architecture model during the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yang Qing)

People visit the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yang Qing)

Pump trucks are seen at the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yang Qing)

Visitors view a drainage pipe during the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yang Qing)

People visit the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yang Qing)

People visit the 2013 China (Shenyang) International Architecture Exposition in Shenyang, capital of Northeast China's Liaoning Province, May 20, 2013. The three-day expo kicked off on Monday, with 615 enterprises from home and abroad participated. (Xinhua/Yang Qing)