等级资料的比较应采用（）
A.四格表x2检验
B.t检验
C.秩和检验
D.F检验
E.R×C表x2检验
参考答案：C
一个底面半径6厘米的圆锥形容器装满水，倒入和它等高的圆柱形容器，倒了6次才倒满，圆柱的底面积是______平方厘米．
It’s John’s birthday today. I wish I _____ her out to a superb restaurant for dinner, but I’m too busy recently.
A．can take
B．take
C．could take
D．had taken
