参考答案

正确答案：D
解析：文章讲到O型血的人是universal donors，但不是universal recipients。因为在第二段最后一句“Persons With blood type AB have no antibodies and can receive any of the four types of blood; thus blood types O and AB are called universal donors and universal recipents, respectively.”中respectively是“各自地，独立地”的意思。同时另一句“In type O blood, neither substance is present on the red cells, but the individual is capable of forming antibodies directed against red cells containing substance A or B.”其句意是：O型血的人红细胞中没有该物质，但个体的人能形成抗A或B型红细胞的抗体。所以，只有O型血的人能给O型人输血。