For four days, the birds were given a choice between two cups of food that were identical except that the food in one was blue in colour because it contained anthocyanins.

在四天里，有两个装着食物的杯子供这些鸟选择。其中一个杯子的食物富含花青素而显得蓝色，除这点以外两个杯子的食物完全相同。

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For four days, the birds were given a choice between two cups of food that were identical except that the food in one was blue in colour because it contained anthocyanins.

在四天里，有两个装着食物的杯子供这些鸟选择。其中一个杯子的食物富含花青素而显得蓝色，除这点以外两个杯子的食物完全相同。

youdao