That'stosay,thetop<em>disintegrates</em>(崩裂)whiletheheavybasestays______ontheroad.Smallerone-pieceversionshavesandinthebasetoachievethesameeffect.Morganmakesupto35,000conesaweekoutofthetotalnationalproductionofabout63,000. A: calmly B: strictly C: safely D: carefully