对于低年级学生而言，采用分数，奖品等外部激励非常有效；但随着年龄的增长，学生必须增强内部学习动机，作为小学教师你认为应该如何有效地培养和激发小学高年级学生的内部学习动机？

I _____ you would come today. You _____ me a phone call in advance.

A．don’t expect; should have given

B．didn’t expect; could have given

C．hadn’t expected; ought to give

D．didn’t expect; can have given