Сомневаюсь в этих вопросах. 1. i was so tired. i sleep for a week. a)could b) can c)must d)might 2. i have not phoned ann for ages. i phone her tonight. a)could b)can c)must d)have 3. if i exams, my go to a disco a) don't pass, won't let b)won't pass, won't let c) won't pass, let d) won't pass, doesn't let заранее, !

the last decades into life of many european cities included the xix century electric lighting. having appeared at first on streets and the areas, it got into each house soon, to each apartment and became an integral part of life of each civilized person. it was one of the major events in the history of the equipment, having huge and diverse consequences. rapid development of electric lighting led to mass electrification, revolution in an energy drink and to large shifts in the industry. however all this could not happen if efforts of many inventors didn't create device such ordinary and habitual for us as an electric bulb. among the greatest opening of human history it, undoubtedly, possesses one of the places of honor. in the xix century two types of electric lamps gained distribution: incandescent lamps and arc. arc bulbs appeared a little earlier. their luminescence is based on such interesting phenomenon, as вольтова an arch. if to take two wires, to connect them to rather strong source of current, to connect, and then to move apart on distance of several millimeters, between the ends of conductors something is formed like a flame with bright light. the phenomenon will be more beautiful and brighter if instead of metal wires to take two pointed coal cores. at rather big tension between them light of dazzling force is formed. for the first time the phenomenon of a volt arch was observed in 1803 by the russian scientist vasily petrov. in 1810 the same discovery was made by english physicist devi. both of them received вольтову an arch, using the big battery of elements, between the ends стерженьков from charcoal. both that, and another wrote that вольтова the arch can be used for lighting. but before it was necessary to find more suitable material for electrodes as cores from charcoal burned down in some minutes and were of little use for practical use. arc lamps had also other inconvenience — in process of burning out of electrodes it was necessary to move constantly them towards each other. as soon as the distance between them exceeded a certain admissible minimum, light of a lamp became rough, it started flickering and died away.

this generation gap is much more important now than at other times. many new technologies were brought to out world. morals changed too. if in the 1960s, 1970s, 1980s children were taught to be modest, humble, kind, what do modern children see in the internet. they see inappropriate material in the internet, learn that money is the key to everything. of course this make difficulties in children-parent conversations and understanding. also parents see what's happening to our world and try to overprotect their children. the latter, as good as they can be, will rebel, just to try something new. this will result in misunderstanding.