某型号的手机去年初售价2180元，经过两次降价后，到今年初售价为1080元，设每次降价的百分率为x（0＜x＜1），可列出求百分率x的方程为______．

Things of ______ kind come together; people of ______ kind fall into ______ same group.[      ]

A. a; the; the

B. a; a; the

C. the; the; the

D. a; a; a