declare [de- = completely 完全；clar = to make clear 使清楚；-e => “to make completely clear 使…完全明白”→]vt. say openly or strongly 宣布；断言/ He declared that he was completely innocent.他宣称自己是完全无辜的。

declaration n. 宣布；宣言 

declarative a. 宣言的；说明的

demand [de- = completely 完全；mand = to order 命令→]vt. ask for as a right or with authority 要求 / The policeman demanded the thief's name.警察要小偷说出姓名。

demandant n. 提出要求者，原告

下面介绍de-与动词相结合生成的派生词。 

decentralize [de-=to undo 取消；centralize v. 集中=>“to undo that of centralizing 取消集中的做法”→]vt. distribute (authority or power)分散(权力等)/ The system of decentralized management took effect immediately. 分散经营的制度立见成效。

decentralization n. 分散权力，权力下放

decompose [de- = to undo 取消；compose 组合 v. =>“to undo that of composing 取消组合的形式”→]vt. separate into what a substance is made of 分解 / A prism decomposes sunlight into its various colours.三棱柱把阳光分解成各种颜色的光。 decomposition n. 分解（作用）；解体

demobilize [de- = to undo 取消；mobilze v. 动员=>“to undo that of mobilizing取消动员军队的状态”→]vt. remove from the army to peacetime life 使复员 / When the war was over, he was demobilized and sent home.战争结束后，他被复员回家。

demobilization n. 复员，遣散