地形起伏: hypsographyland waveroughness of relieftopographic inequalitytopographic relief
长期: over a long period of time; long-term; long range; secular 短语和例子作长期打算 take a long view; make long-term plans; 长期观点 a long-term view; 长期存在的问题 a long-standing problem; 这个实验结果长期不显著。 the resul
长期肝胆相照: treat each other with all sincerity on a long-term basis
长期观测站: continuous stationlong term stationlong-established stationlong-term station
长期预测: long range forecastlong range predictionlong range projectionlong run predictionlong term forecastlong term projectionlong-range predictionlong-run forecastlong-term forecastinglong-term p
