最初对黑色的偏好在十三、十四世纪改变了，因为红色、紫罗兰色和紫色开始流行。
The original preference for black was changed in the thirteenth and fourteenth centuries, as such colors as red, violet and purple came into fashion.
其中一些选择可能会根据特定的情况或个人的偏好而改变顺序；例如，手写便条可能比语音邮件更加私人化。
Some of these may change order according to the specific situation or your own preferences; for example, a handwritten note might seem more personal than voice-mail.
故此，使效用加倍无法改变消费者的偏好。
Thus, doubling the utility doesn't change the preferences of the consumer.
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