When we breath the air enters the body through the nose and mouth. It then passes on through an opening in the back part of the throat into the windpipe, or trachea. Our windpipe…

When we breath the air enters the body through the nose and mouth. It then passes on through an opening in the back part of the throat into the windpipe, or trachea. Our windpipe is divided into two parts when it reaches the lungs. One bronchial tube goes to the right lung and the other one to the left lung. Within the lungs, each bronchial tube divides into smaller ones which continue to divide again and again. Each little tube finally ends in a great number of tiny air cells. They act as reservoirs to hold the air while the exchange between the oxygen and the carbon dioxide takes place. A network of tiny capillaries runs în all directions in the walls of the air cells. So the blood is able to come into the lungs and to bring the red corpuscles very close to the oxygen. The real work of respiration takes place in these tiny air cells of the lungs. It is here that the red corpuscles give up their carbon dioxide and take the oxygen from the air in exchange. It is interesting to note that the blood and the air do not come into contact in this exchange. When the blood enters the lungs it comes into the tiny capillaries which may be found in the walls of the air cells. The walls of the air cells and the capillaries are so thin that the oxygen passes through them from the air cells into the blood, while the waste carbon dioxide passes easily through them from the blood into the air cells. The oxygen is then taken up by the red corpuscles in the blood while the waste carbon dioxide is forced out of the air cells by the process of expiration. Notes to the text: red corpuscles - эритроциты Задания: Найдите в тексте: 1. сказуемые в действительном и страдательном залогах. Определите их время; 2. модальные глаголы и их эквиваленты; 3. усилительный оборот; 4. "опе" и в разных функциях; 5. причастия.