"A cavity full of lofty sentiments, a hundred battles of foolishness, and windy sand and green mountains and rivers" is an environmental protection slogan, which means to have the spirit of moving mountains with foolishness, adhere to green environmental protection, plant trees, build an ecological security barrier, and make mountains greener, water clearer and forests denser. This sentence emphasizes the enthusiasm and determination for environmental protection, and we should use unremitting efforts and practical actions to protect the environment and improve the ecology.