Zhou Xing, a middle school student, shows his invention during a youth science and technology innovation competition in Nanning, capital of south China's Guangxi Zhuang Autonomous Region, March 23, 2018. (Xinhua/Zhang Ailin)

A pupil shows a hanger she designed for people on trips during a youth science and technology innovation competition in Nanning, capital of south China's Guangxi Zhuang Autonomous Region, March 23, 2018. (Xinhua/Zhang Ailin)

Deng Yeyang, a middle school student, shows his invention during a youth science and technology innovation competition in Nanning, capital of south China's Guangxi Zhuang Autonomous Region, March 23, 2018. (Xinhua/Zhang Ailin)

People visit a youth science and technology innovation competition in Nanning, capital of south China's Guangxi Zhuang Autonomous Region, March 23, 2018. (Xinhua/Zhang Ailin)