单项选择题
A．a bad impact on other industries B．a change of tourists'customs C．overcrowdedness of places of interest D．pressure on traffic
A．an increase of unemployment B．a decrease in tourist attractions C．the higher cost of support facilities D．a rise in price and a fall in pay
A．It is extremely important to develop tourism. B．Building roads and hotels is essential. C．Support facilities are highly necessary. D．Planning is of great importance to tourism.