题目

 What do you mean, there are only ten tickets? There        be twelve.A. must               B. can                  C. will                         D. should 答案：D一个圆的半径由2厘米增加到3厘米,那么这个圆的面积增加了(　　)平方厘米。A. 12.56 B. 28.26 C. 15.7 D. 3.14