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* Read the following passage and mark the letter A, R, C, or D on your answer sheet to indicate the correct answer to each of the questions from 24 to 30.   People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical procedures. 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.   Transfusing the blood from the donor to the recipient is straightforward. It involves taking the blood from a donor’s arm vein by means of a hypodermic syringe. 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 from 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.   Negative reactions to transfusions are not unusual. The recipient may suffer an allergic reaction or be sensitive to donor leukocytes. Some may suffer from an undetected red cell incompatibility. Unexplained reactions are also fairly common. Although they are rare, other causes of such negative reactions include contaminated blood, air bubbles in the blood, overloading of the circulatory system through administration of excess blood, or sensitivity to donor plasma or platelets.   Today, hospitals and blood banks go to great lengths to screen all blood donors and their blood. All donated blood is routinely and rigorously tested for diseases, such as HIV, hepatitis B, and syphilis. When the recipient is a newborn or an infant, the blood is usually irradiated to eliminate harmful elements. Donated blood is washed, and the white blood cells and platelets removed.   Storing the blood sometimes requires a freezing process. To freeze the red blood cells, a glycerol solution is added. To unfreeze the, the glycerolis removed. The ability to store blood for long periods has been a boon to human health.What does the author imply in the passage?

Xem chi tiết 9.5 K lượt xem 6 năm trước

  * Read the following passage and mark the letter A, R, C, or D on your answer sheet to indicate the correct answer to each of the questions from 24 to 30.   People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical procedures. 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.   Transfusing the blood from the donor to the recipient is straightforward. It involves taking the blood from a donor’s arm vein by means of a hypodermic syringe. 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 from 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.   Negative reactions to transfusions are not unusual. The recipient may suffer an allergic reaction or be sensitive to donor leukocytes. Some may suffer from an undetected red cell incompatibility. Unexplained reactions are also fairly common. Although they are rare, other causes of such negative reactions include contaminated blood, air bubbles in the blood, overloading of the circulatory system through administration of excess blood, or sensitivity to donor plasma or platelets.   Today, hospitals and blood banks go to great lengths to screen all blood donors and their blood. All donated blood is routinely and rigorously tested for diseases, such as HIV, hepatitis B, and syphilis. When the recipient is a newborn or an infant, the blood is usually irradiated to eliminate harmful elements. Donated blood is washed, and the white blood cells and platelets removed.   Storing the blood sometimes requires a freezing process. To freeze the red blood cells, a glycerol solution is added. To unfreeze the, the glycerolis removed. The ability to store blood for long periods has been a boon to human health.     Based on the information in the passage, what can be inferred about blood transfused to infants and newborns?  

Xem chi tiết 3.3 K lượt xem 6 năm trước

* Read the following passage and mark the letter A, R, C, or D on your answer sheet to indicate the correct answer to each of the questions from 24 to 30.   People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical procedures. 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.   Transfusing the blood from the donor to the recipient is straightforward. It involves taking the blood from a donor’s arm vein by means of a hypodermic syringe. 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 from 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.   Negative reactions to transfusions are not unusual. The recipient may suffer an allergic reaction or be sensitive to donor leukocytes. Some may suffer from an undetected red cell incompatibility. Unexplained reactions are also fairly common. Although they are rare, other causes of such negative reactions include contaminated blood, air bubbles in the blood, overloading of the circulatory system through administration of excess blood, or sensitivity to donor plasma or platelets.   Today, hospitals and blood banks go to great lengths to screen all blood donors and their blood. All donated blood is routinely and rigorously tested for diseases, such as HIV, hepatitis B, and syphilis. When the recipient is a newborn or an infant, the blood is usually irradiated to eliminate harmful elements. Donated blood is washed, and the white blood cells and platelets removed.   Storing the blood sometimes requires a freezing process. To freeze the red blood cells, a glycerol solution is added. To unfreeze the, the glycerolis removed. The ability to store blood for long periods has been a boon to human health.         What can the phrase "go to great length" best replaced by?

Xem chi tiết 641 lượt xem 6 năm trước

* Read the following passage and mark the letter A, R, C, or D on your answer sheet to indicate the correct answer to each of the questions from 24 to 30.   People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical procedures. 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.   Transfusing the blood from the donor to the recipient is straightforward. It involves taking the blood from a donor’s arm vein by means of a hypodermic syringe. 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 from 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.   Negative reactions to transfusions are not unusual. The recipient may suffer an allergic reaction or be sensitive to donor leukocytes. Some may suffer from an undetected red cell incompatibility. Unexplained reactions are also fairly common. Although they are rare, other causes of such negative reactions include contaminated blood, air bubbles in the blood, overloading of the circulatory system through administration of excess blood, or sensitivity to donor plasma or platelets.   Today, hospitals and blood banks go to great lengths to screen all blood donors and their blood. All donated blood is routinely and rigorously tested for diseases, such as HIV, hepatitis B, and syphilis. When the recipient is a newborn or an infant, the blood is usually irradiated to eliminate harmful elements. Donated blood is washed, and the white blood cells and platelets removed.   Storing the blood sometimes requires a freezing process. To freeze the red blood cells, a glycerol solution is added. To unfreeze the, the glycerolis removed. The ability to store blood for long periods has been a boon to human health.           What answer choice is closest in meaning to the word “undetected”?

Xem chi tiết 1.4 K lượt xem 6 năm trước

* Read the following passage and mark the letter A, R, C, or D on your answer sheet to indicate the correct answer to each of the questions from 24 to 30.   People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical procedures. 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.   Transfusing the blood from the donor to the recipient is straightforward. It involves taking the blood from a donor’s arm vein by means of a hypodermic syringe. 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 from 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.   Negative reactions to transfusions are not unusual. The recipient may suffer an allergic reaction or be sensitive to donor leukocytes. Some may suffer from an undetected red cell incompatibility. Unexplained reactions are also fairly common. Although they are rare, other causes of such negative reactions include contaminated blood, air bubbles in the blood, overloading of the circulatory system through administration of excess blood, or sensitivity to donor plasma or platelets.   Today, hospitals and blood banks go to great lengths to screen all blood donors and their blood. All donated blood is routinely and rigorously tested for diseases, such as HIV, hepatitis B, and syphilis. When the recipient is a newborn or an infant, the blood is usually irradiated to eliminate harmful elements. Donated blood is washed, and the white blood cells and platelets removed.   Storing the blood sometimes requires a freezing process. To freeze the red blood cells, a glycerol solution is added. To unfreeze the, the glycerolis removed. The ability to store blood for long periods has been a boon to human health.           All of the following are mentioned as potential negative reactions to transfusion EXCEPT__________.

Xem chi tiết 1.2 K lượt xem 6 năm trước

* Read the following passage and mark the letter A, R, C, or D on your answer sheet to indicate the correct answer to each of the questions from 24 to 30.   People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical procedures. 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.   Transfusing the blood from the donor to the recipient is straightforward. It involves taking the blood from a donor’s arm vein by means of a hypodermic syringe. 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 from 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.   Negative reactions to transfusions are not unusual. The recipient may suffer an allergic reaction or be sensitive to donor leukocytes. Some may suffer from an undetected red cell incompatibility. Unexplained reactions are also fairly common. Although they are rare, other causes of such negative reactions include contaminated blood, air bubbles in the blood, overloading of the circulatory system through administration of excess blood, or sensitivity to donor plasma or platelets.   Today, hospitals and blood banks go to great lengths to screen all blood donors and their blood. All donated blood is routinely and rigorously tested for diseases, such as HIV, hepatitis B, and syphilis. When the recipient is a newborn or an infant, the blood is usually irradiated to eliminate harmful elements. Donated blood is washed, and the white blood cells and platelets removed.   Storing the blood sometimes requires a freezing process. To freeze the red blood cells, a glycerol solution is added. To unfreeze the, the glycerolis removed. The ability to store blood for long periods has been a boon to human health.           According to the passage, how often can people donate blood for red blood cells?

Xem chi tiết 1.9 K lượt xem 6 năm trước

* Read the following passage and mark the letter A, R, C, or D on your answer sheet to indicate the correct answer to each of the questions from 24 to 30.   People have been donating blood since the early twentieth century to help accident victims and patients undergoing surgical procedures. 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.   Transfusing the blood from the donor to the recipient is straightforward. It involves taking the blood from a donor’s arm vein by means of a hypodermic syringe. 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 from 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.   Negative reactions to transfusions are not unusual. The recipient may suffer an allergic reaction or be sensitive to donor leukocytes. Some may suffer from an undetected red cell incompatibility. Unexplained reactions are also fairly common. Although they are rare, other causes of such negative reactions include contaminated blood, air bubbles in the blood, overloading of the circulatory system through administration of excess blood, or sensitivity to donor plasma or platelets.   Today, hospitals and blood banks go to great lengths to screen all blood donors and their blood. All donated blood is routinely and rigorously tested for diseases, such as HIV, hepatitis B, and syphilis. When the recipient is a newborn or an infant, the blood is usually irradiated to eliminate harmful elements. Donated blood is washed, and the white blood cells and platelets removed.   Storing the blood sometimes requires a freezing process. To freeze the red blood cells, a glycerol solution is added. To unfreeze the, the glycerolis removed. The ability to store blood for long periods has been a boon to human health. The word "it" refers to___________.

Xem chi tiết 3.3 K lượt xem 6 năm trước

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.   Biological diversity has become widely recognized as a critical conservation issue only in the past two decades. The rapid destruction of the tropical rain forests, which are the ecosystems with the highest known species diversity on Earth, has awakened people to the importance and fragility of biological diversity. The high rate of species extinctions in these environments is jolting, but it is important to recognize the significance of biological diversity in all ecosystems. As the human population continues to expand, it will negatively affect one after another of Earth’s ecosystems. In terrestrial ecosystems and in fringe marine ecosystems (such as wetlands), the most common problem is habitat destruction. In most situations, the result is irreversible. Now humans are beginning to destroy marine ecosystems through other types of activities, such as disposal and runoff of poisonous waste; in less than two centuries, by significantly reducing the variety of species on Earth, they have irrevocably redirected the course of evolution.   Certainly, there have been periods in Earth’s history when mass extinctions have occurred. The extinction of the dinosaurs was caused by some physical event, either climatic or cosmic. There have also been less dramatic extinctions, as when natural competition between species reached an extreme conclusion. Only 0.01 percent of the species that have lived on Earth have survived to the present, and it was largely chance that determined which species survived and which died out.   However, nothing has ever equaled the magnitude and speed with which the human species is altering the physical and chemical world and demolishing the environment. In fact, there is wide agreement that it is the rate of change humans are inflicting, even more than the changes themselves, that will lead to biological devastation. Life on Earth has continually been in flux as slow physical and chemical changes have occurred on Earth, but life needs time to adapt-time for migration and genetic adaptation within existing species and time for the proliferation of new genetic material and new species that may be able to survive in new environments. What does the passage mainly discuss?

Xem chi tiết 1 K lượt xem 1 năm trước