少数情况下，动物冠状病毒会进化并在人群中传播，如中东呼吸综合征和严重急性呼吸综合征（SARS）。

Rarely, animal corona-viruses can evolve and then spread among people, such as Middle East respiratory syndrome and severe acute respiratory syndrome (SARS).

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病窦综合征也可能由窦房结附近的瘢痕组织引起，后者会减慢、干扰、或是阻断电冲动的传导。

Sick sinus can also be caused by scarring near the sinus node that's slowing, disrupting or blocking the travel of impulses.

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这表明，妇女如果在孕期饮酒过多，表观遗传变异可能会导致他们的子女出现胎儿酒精综合征中的一些固定症状。

This suggests that if women drink too much in pregnancy, epigenetic changes may cause some of the permanent symptoms seen in fetal alcohol syndrome in their children.

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