I hear one of them________ a baby.填has,tohave,are having ,have
问题描述：
I hear one of them________ a baby.填has,tohave,are having ,have
答
has
答
I hear 后街句子时句子的时态还是随主语的.
这句I hear 后面的句子主语是one of them,他们中的一个,所以用单数.
因此,选has,其他皆排除.