回答61-65题：

　　Blood vessels running all through the lungs carry blood to each air sac (囊), or alveolus(肺泡), and then back again to the heart. Only the thin wall of the air sac and the thin wall of a capillary (毛细血管) are between the air and the blood. So oxygen easily diffuses from the air sacs through the walls into the blood, while carbon dioxide easily diffuses from the blood through the walls into the air sacs.

　　When blood is sent to the lungs by the heart, it has come back from the cells in the rest of the body. So the blood that goes into the wall of an air sac contains much dissolved carbon dioxide but very little oxygen. At the same time, the air that goes into the air sac contains much oxygen but very little carbon dioxide. You have learned that dissolved materials always diffuse from where there is more of them to where there is less. Oxygen from the air dissolves in the moisture on the lining of the air sac and diffuses through the lining into the blood. Meanwhile, carbon dioxide diffuses from the blood into the air sac. The blood then flows from the lungs back to the heart, which sends it out to all other parts of the body.

　　Soon after air goes into an air sac, it gives up some of its oxygen and takes in some carbon dioxide from the blood. To keep diffusion going as it should, this carbon dioxide must be gotten rid of. Breathing, which is caused by movements of the chest, forces the used air out of the air sacs in your lungs and brings in fresh air. The breathing muscles are controlled automatically so that you breathe at the proper rote to keep your air sacs supplied with fresh air. Ordinarily, you breathe about twenty-two times a minute. Of course, you breathe faster when you are exercising and slower when you are resting. Fresh air is brought into your lungs when you breathe in, or inhale (吸入), while used air is forced out of your lungs when you breathe out, or exhale.

　　Some people think that all the oxygen is taken out of the air in the lungs and that what we breathe out is pure carbon dioxide. But these ideas are not correct. Air is a mixture of gases that is mostly nitrogen(氮). This gas is not used in the body. So the amount of nitrogen does not change as air is breathed in and out. But while air is in the lungs, it is changed in three ways: ( 1 ) About one-fifth of the oxygen in the air goes into the blood. (2) An almost equal amount of carbon dioxide comes out of the blood into the air. (3) Moisture from the linings of the air passages and air sacs evaporates until the air is almost saturated.

　　61、It can be inferred from the passage that oxygen and carbon dioxide _______.

　　A.produce energy for breathing

　　B.diffuse immediately in the blood

　　C.penetrate slowly into the air sacs

　　D.travel in opposite ways in the lungs

　　62、When blood travels back to the lungs by the heart, ________.

　　A.more oxygen was contained in blood

　　B.more carbon dioxide was contained in the blood

　　C.less carbon dioxide was contained in an air sac

　　D.less oxygen was contained in an air sac

　　63、The movement of breathing can effectively ________.

　　A.help the exchange of oxygen and carbon dioxide in the lungs

　　B.prevent the inhaling of excessive carbon dioxide

　　C.keep the regular circulation of blood

　　D.strengthen the function of breathing muscles

　　64、When we breathe out, the amount of nitrogen ________.

　　A.increases a bit because of the exchange of air

　　B.reduces a bit because of the exchange of air

　　C.remains the same as we breathe it in

　　D.keeps the same as that needed in lungs

　　65、The air in the lungs changes through ________.

　　A.inhaling some amount of oxygen

　　B.the evaporation of moisture

　　C.exhaling some amount of carbon dioxide

　　D.generating a passage for evaporation

　　Part VI Translation (30 minutes)

　　Directions: For this part, you are allowed 30 minutes to translate a passage from Chinese into English. You should write your answer on Answer Sheet 2.

　　要了解中国文化，就应该对中国的戏曲文化有所了解。中国地方戏种类很多，其中京剧是一个具有代表性的剧种。作为一个独立的剧种，京剧的诞生大约是在1840年至l860 。京剧是在吸收其他地方戏营养的基础上形成的。京剧有明确的角色分工;在念白上用北京方言;在音乐上以胡琴为主要伴奏乐器。由于京剧是在融合各种地方戏之精华的基础上形成的，所以它不仅为北京的观众所钟爱，也受到全国人民的喜爱。

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