I can't believe what he says because he is changing his mind. .A. regularlyB. steadilyC.

问题补充：

I can believe what he says because he is changing his mind. .

A. regularly

B. steadily

C. suddenly

D. constantly

答案：

A. regularly

B. steadily

C. suddenly

(答案→)D. constantly

解析：

试题分析:考查副词辨析。A定期地；B稳定地；C突然地；D持续地。根据语境判断D选项正确，因为他不断地改主意才不能相信他，句意：我不能相信他说的话，因为他总是改变主意。