Simply put, you are A, B, AB or O depending on if you have A antigens, B antigens, both antigens or neither of the antigens.

简单的来说，根据你的抗原是A型、B型、AB型，还是没有抗原而将你区分成A型血、B型血、AB型血和O型血。

So if you don't have a particular antigen on your blood cells — say the type B — then you do have antibodies that are going to label those B antigens for attack, should they enter your space.

所以如果你的血细胞上没有特定的抗原——比如说 B 型——那么你有抗体来标记这些 B 型抗原，一旦它们进入你的空间，它们就会攻击。