[单选] Threefourths of the homework（）today.

A . has finished
B . has been finished
C . have finished
D . have been finished

流动性偏好理论是（）建立和发展起来的。俄林。罗勃逊。凯恩斯。马克思。职业健康体检和一般健康体检有何区别？发生火险时不能采用的方式是（）坐电梯逃生。用湿毛巾捂住口鼻。采取低姿势前进。用湿棉被捂堵门。从幻灯片的放映状态切换回编辑状态，应使用（）键。 F5。 ESC。 Ctrl+Alt。 Ta。机器人是对（）的复制品。机器。动物。人类。电脑。 Threefourths of the homework（）today.

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