题目

 The new books are of great use. They  ____ well and ____ already.A. sell;  sell out                           B. sold; had sold outC. sold; have sold out                  D. sell; have been sold out 答案：D一个空瓶，装满水后总质量为32g，装满酒精后总质量为28g，则空瓶质量和容积分别是（　　）A．14g、14cm3B．12g、20cm3C．28g、28cm3D．24g、40cm3