sag /sæɡ/ vi.（中间部分）下垂：The shelf was beginning to sag beneath the weight of the books upon it. 书架在书的重压下渐渐下弯。He closed his eyes and sagged against the wall.他闭上眼睛，瘫靠在墙上。Exports are forging ahead while home sales sag.出口在稳步上升而国内销售额却下降了。