fluctuant; rolling; undulant; undulate; undulatory; up-and-down

1. 砂丘相對平坦或有波狀起伏的覆草沙地，通常在海岸邊
   Relatively flat or undulating sandy turf-covered ground usually along a seashore.
2. 起伏的山丘逐漸向海岸緩降
   The rolling hills fall gently toward the coast.
3. 該市為平緩起伏的丘陵所圍繞著。
   The city is girdled about with gently rolling hills.
4. 大草原多為廣闊而無樹木的平坦或起伏的草原區(qū)域，尤指北美洲中部的大平原
   An extensive area of flat or rolling, predominantly treeless grassland, especially the large tract or plain of central North America.

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