another important function of the kidney is to maintain the proper balance of water, salt and acid in the body fluids. the brain is the main center for regulating and coordinating body activities. respiration is the mechanical process of breathing. the blood and lymphatic systems have many functions . joints are the places where bones come together. the endocrine system is composed of glands located in different regions of the body. exercise 6. вставьте артикль там, где необходимо. main systems of the body have groups of organs working together to perform complex functions. … mouth, esophagus, stomach, small and large intestines are organs which compose the digestive system. there are some organs within each system. The circulatory system is also called a cardiovascular system. the main function of the respiratory system is to convey oxygen and to remove carbon dioxide
Put the verbs in brackets in the Past Simple or in the Present Perfect.
1. I have never been
(never/be) to the USA.
2. He has lived
(live) in this street all his life.
3. His father didn't come
(not come back) to London last Sunday.
4. Yan wrote
(write) a letter to Nick two days ago.
5. Did he send
(send) his letter yesterday?
6. They have just bought
(just/ buy) some postcards?
7. I (have, just) have just had
a nice pot of coffee. Would you like a cup?
8. I (see, not) haven't seen
Steve this morning yet.
9. I (not go) didn't go
to Paris in 2003 and 2006.
10. I (be) have never been
to Italy.