The COVID-19 pandemic has dealt a heavy blow to the world economy.Many large-scale international exhibitions have been canceled or postponed,which has affected
CIFTIS(the China International Fair for Trade in Services)was held in Beijing in September,2020.As the world’s first comprehensive exhibition of trade in servi
In recent years,the development of the unmanned aerial vehicle(UAV)market has become popular due to the convenient uses of UAVs in both civilian and commercial