backgrounder记者招待会backgroundn.背景；经历；幕后；后景vt.提供背景background illuminate背景照明background build-up本底增长background of writing创作契机background suppressed背景抑制Background of Germany德国概况Background conditions背景条件background of feeling感觉的背景background estimation背景估计background trend line本底趋势线background fade-out背景淡出