grayback英美n. 灰色动物(如:灰鲸,黑头鸦,斑背潜鸭等)英英释义nouna sandpiper that breeds in the Arctic and winters in the southern hemisphereSynonym:knotgreybackCalidris canutusa dowitcher with a grey backSynonym:greybackLimnodromus griseus