煮濃,熬濃,壓縮
boil down v 1: be the essential element; "The proposal boils down to a compromise" [syn: {reduce}, {come down}] 2: be cooked until very little liquid is left; "The sauce should reduce to one cup" [syn: {reduce}, {decoct}, {concentrate}] 3: cook until very little liquid is left; "The cook reduced the sauce by boiling it for a long time" [syn: {reduce}, {concentrate}]