________ be a history teacher? [ ]

A. Did she used to

B. Does she use to

C. Did she use to

D. Does she used to

自然保费和均衡保费是人寿保险的两种保费形式，两者之间的关系是______。

A．在保单初期自然保费大于均衡保费
B．在保单初期自然保费等于均衡保费
C．在保单后期自然保费小于均衡保费
D．在保单后期自然保费大于均衡保费