Тут написанны загадки, и первая буква ответов! 1) the process of making air, water, soil, etc.dirty 2)using something again and again 3)it is a flat surface on a computer where you see pictures and words 4)it is low land between hills or mountains ​

1. everyone enjoyed the singing of this song. 2. sitting near a window, he was smoking, . 3. smoking is harmful for health. 4. this article was written by a student. 5. lying on a sofa, we was reading a book. 6. a text will be translated until five o'clock. 7. a letter is already written. 8. many newspapers and magazines are printed every day. 9. this opera was written one hundred years ago. 10. are the books already brought from a library? 11. a translation of this text was difficult for me. 12. working in a garden is useful for health. 13. a young man, who is sitting near a window, is my brother. 14. this story was discussed on a literarure lesson one week ago. 15. this article will be published tomorrow until three o'clock. 16. a director was already sent for. 17. this text is often translated on lessons. 18. i think about going to the sea in summer. 19. will i be invited for your evening party? 20. this question is still being discussed on a meeting.

Unidentified flying object (ufo) (eng. unidentified flying object, ufo) — observed an object resembling a flying machine, which was not recognized by earthly observers. the most complete definition of a ufo was given by the investigator of the unknown, joseph allen hynek: "the perception of an object or light seen in the sky or space or above the earth's surface; a phenomenon, ghost, trajectory, and general dynamics and the nature of the luminescence which does not find a logical, conventional explanation, is a mystery not only for witnesses, but remains unexplained even after a careful study of all available evidence by experts who can, if possible, to identify the phenomenon from the point of view of common sense"[2]. in other words, if a message appears on earth observation any strange phenomenon, the case has not been identified with any known science, meteorological or astronomical phenomenon, nor has it been installed, evidence of tampering, then we say that we are talking about unidentified flying object (ufo). if the explanation for the phenomenon was found, then we talk about identified flying objects (olo). most of the flying objects still finds the explanation and becomes olo. of all the posts on obscure flying objects remain unidentified only 5-10 %[3]. some objects remain unidentified only because of the lack of information about them. because of documented cases of sightings of flying objects some to identify failed, the greatest skepticism usually cause no messages about seeing something unidentified, and that assertions about the alien origin of objects. in many countries (including usa and ussr) cases of ufo sightings recorded by authorized military and civilian government agencies, including within the classified special government programs (project "blue book" and aa). the secrecy may have contributed to the emergence of public interest in the phenomenon. at least, the american historian greg eghigian (greg eghigian), which examined how changing ideas about ufos and the attitude towards them, came to the conclusion that ufos were a product of the cold war and the related culture of secrecy and distrust[4]. in different countries there are many social action organizations and enthusiasts dedicated to recording and analysis of ufo phenomena, including in russia — kosmopoisk. from a scientific point of view, still there is no confirmed evidence that ufos are in any way related to alien life, and the first official contact is a lot of science fiction and the future. while supporters of the extraterrestrial origin of the observed ufo is only a small part of scientists, the official scientific community of the world has an extensive program of search for extraterrestrial intelligence seti, which suggests the possibility of detection activities of extraterrestrial intelligence within the framework of the research with the help of technical means are possible manifestations of this activity in the near and far space. with the development of computer technologies and the internet in the program began to be carried out distributed processing of the information on thousands of ordinary computers. in mass culture by the ufo often means unidentified flying object, the appearance of which is associated with the visit to earth of intelligent beings[5]. many people, including officials and scholars are skeptical about the ability of these visits and are convinced (or, in the opinion of ufologists, pretending to believe) that the ufo phenomenon is an anomalous natural phenomenon. on the contrary, some former officials, military personnel and astronauts (including lunar astronaut edgar mitchell, inspired by then parapsychology[6]), after leaving the service become public supporters of the extraterrestrial origin of ufos.