题目

 The new lab being built will be ______ the present one.    A. as three times big as                  C. three times as big as    C. as big as three times                  D. as big three times as 答案：C若⊙O1与⊙O2的半径分别5和4，如果两圆内切，那么圆心距d的值是    ．