劍橋詞典a plant of North America and Australia that breaks near the ground when it dies , and forms large balls that are rolled around by the wind 風(fēng)滾草（生長(zhǎng)於北美和澳大利亞，枯萎後在地麪処折落，隨風(fēng)像球一樣四処滾動(dòng)） 返回 tumbleweed