【单选题】The four blood types are【C1】______as A, B, AB, and O. Blood type A【C2】______red blood cells that have a substance A on their surface. This type of blood also contains an antibody directed【C3】______sub...
【简答题】阅读理解。 Many hospitals have blood banks. In these banks, blood of all types is stored. When blood is needed, it is taken from the bank. Healthy people then give blood to the bank to replace (取代) the blo...