题目

________ for the doctor's careful treatment, he ________ till last year. A . If it were not, can't live B . Were it not, couldn't live C . Had it not been, couldn't have lived D . If they were not, couldn't live 答案：C在面积一定的一组菱形中，当菱形的一条对角线长为2.5cm时，它的另一条对角线长为8cm，若其中一个菱形的对角线长为10cm时，它的另一条对角线长为      cm．