某电场中等势面分布如图所示，图中虚线表示等势面，过a、c两点的等势面电势分别为40 V和10 V，则a、c连线的中点b处的电势应(　　)

A．小于25 V

B．大于25 V

C．肯定等于25 V

D．可能等于25

I thought her nice and honest ____ I met him.  [ ]

A. first time  

B. for the first time  

C. the first time  

D. by the first time