甲、乙两块矿石的质量相等,甲的体积是乙的2倍。若将甲切去1/3,将乙切去2/3,则剩下的两块矿石密度的大小关系是ρ甲=ρ乙。 答案:【1】12– ______ a year do people in the USA celebrate Halloween?– Once a year. I would like to dress up _______ an old woman.A. How often; as B. How many times; asC. How long; for D. How far; to