Read the following passage and choose the best answer (A, B, C, D):
People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical (1)_____. Usually a pint of whole blood is donated, and it is then divided into platelets, white blood cells, and red blood cells. People can donate blood (for red blood cells) about once every two months. (2) ____ the blood from the donor to the recipient is straightforward. It involves (3) _____ the blood from a donor’s arm vein by means of a hypodermic syringe. The blood flows through a plastic tube to a collection bag or bottle (4)_______ contains sodium citrate, which prevents the blood from clotting. When the blood is given to a patient, a plastic tube and hypodermic needle are connected to the recipient’s arm. The blood flows down from the container by gravity. This is a slow process and may last as long as 2 hours to complete the infusion of blood into the recipient. The patient is protected (5)______ being infected during the transfusion. Only sterile containers, tubing, and needles are used, and this helps ensure that transfused or stored blood is not exposed to disease causing bacteria

Suy nghĩ và trả lời câu hỏi trước khi xem đáp án

ATNETWORK
ADMICRO
YOMEDIA
ZUNIA9