The fry suffered from a peak of death during 7 th to 9 th day and the color of fry changed from reddish brown to black obviously around the 11 th day.

孵出后的仔鱼在第7~9天为死亡高峰期，第11天左右的仔鱼体色有明显的变化，由棕红色变为黑色。

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For these reasons, manorial economy of England reached its peak at the end of the 13 ~ (th) century.

在此管理体制、方法及思想的共同作用下，英国庄园经济于十三世纪末达到其鼎盛时期。

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