公营体制、私营体制、国营体制是目前世界上典型的三种媒介体制。
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(cosx)'
A. -sinx
B. sinx
C. cosx
D. -cosx
黄化幼苗的光敏色素含量比绿色幼苗____,光敏色素是一种易溶于水的____。
光敏色素有两种类型: ____和____,其中____型是生理激活型,____型是生理失活____型。
【单选题】The general considered all the information that had been gathered and _________ what possible moves the enemy might make before issuing his orders.
A. guarded
B. guided
C. guaranteed
D. gauged