行政领导者的要素是（）。
A.行政领导职权
B.行政领导产生方式
C.行政领导职务
D.行政领导责任
参考答案：A, C, D
— We expected you yesterday.
— I'm sorry, I ____ you to say that I couldn't be here until today. [ ]
A. must have called
B. would be calling
C. could have been calling
D. should have called
普遍优惠制的特点是：（）和（）。
