The significance of understanding the seasonal characteristics of tourism activities lies in (　).

Answers: A, B, D

For tourist destinations, the significance of understanding the characteristics of seasonality includes: ① It helps to understand the harm of seasonality to the tourism industry The seriousness of the operation; ② it is necessary to build and promote tourist destinations suitable for visiting all year round; ③ it is necessary to focus on the planning and development of tourist routes, especially the planning and development of off-season products with selling points.