Total absence of a nasal bone on a fetus during the second trimester can identify nearly half of all fetuses affected by Down syndrome.

是将近一半的胎儿患有唐氏综合征还是近一半患有唐氏综合征的胎儿没有鼻骨？

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Total absence of a nasal bone on a fetus during the second trimester can identify nearly half of all fetuses affected by Down syndrome.

是将近一半的胎儿患有唐氏综合征还是近一半患有唐氏综合征的胎儿没有鼻骨？

youdao