流动: 1.(液体或气体移动) flow; run; circulate 短语和例子河水缓缓地流动。 the river is flowing slowly. 空气流动。 the air is circulating.2.(经常变换位置) going from place to place; on the move; mobile 短语和例子流动电影放映队 mobile film
城市: city; town; [波斯] abad; conurbation (有许多卫星城镇的大城市)◇城市卫生 city health; urban health; 城市污染 municipal pollution; 城市污水 municipal sewage; 城市小公园 a vest-pocket park; 城市住房 town house; 城市住宅区 uptown