Качественный перевод теста.- the engine 1. the engine is the source of power that makes the car move. it is usually called an internal combustion engine because gasoline is burned within its cylinders or combustion chambers. most automobile engines have six or eight cylinders. 2. the operating cycle of the four-stroke engine that takes place in the engine cylinder can be divided into four strokes. the upper limit of the piston movement is called the top dead centre. the lower limit of piston movement is called the bottom dead centre. a stroke is the piston movement from the top dead centre to the bottom dead centre, or from the bottom dead centre to the top dead centre in other words, the piston completes a stroke each time it changes the direction of its motion. 3. where the entire cycle of events in the cylinder requires four strokes (two crankshaft revolutions), the engine is called a four-stroke cycle engine. the four strokes are: intake, compression, power and exhaust. 4. two-cycle engines have also been made, and in such engines the entire cycle of events is completed in two strokes or one revolution of the crankshaft. 5. on the intake stroke the intake valve is opened. the mixture of air and vaporized gasoline is delivered into the cylinder through the inlet valve. on the compression stroke the inlet valve is closed so that the mixture can be compressed. on the power stroke both valves (inlet and exhaust) are closed in order to rise pressure during the mixture combustion. on the exhaust stroke the exhaust valve is opened to exhaust the residual gas.

1. двигатель является источником мощности, который заставляет автомобиль двигаться. его обычно называют двигателем внутреннего сгорания, потому что бензин сжигается внутри его цилиндров или камер сгорания. большинство автомобильных двигателей имеют шесть или восемь цилиндров.2. рабочий цикл четырехтактного двигателя, который имеет место в цилиндре двигателя, можно разделить на четыре хода. верхняя граница движения поршня называется верхней мертвой точкой. нижняя граница движения поршня называется нижней мертвой точкой. ход поршня перемещается от верхней мертвой точки к нижней мертвой точке или изнижней мертвой точки до верхней мертвой точки. другими словами, поршень завершает ход каждый раз, когда он меняет направление его движения.3. если для всего цикла событий в цилиндре требуется четыре хода (два оборота коленчатого вала), двигатель называется четырехтактным двигателем. четыре : потребление, сжатие, мощность и выхлоп.4. также были изготовлены двухтактные двигатели, и в таких двигателях весь цикл событий завершается двумя или одним оборотом коленчатого вала.5. на входе впускной клапан открывается. смесь воздуха и испаренного бензина поступает в цилиндр через впускной клапан.по ходу сжатия впускной клапан закрывается, так что смесь может быть сжата.при сильном ходу оба клапана (впускные и выпускные) закрываются для повышения давления во время сгорания смеси.по ходу выхлопа выпускной клапан открывается, чтобы выпустить остаточный газ.

David livingstone was a christian missionary and one of the greatest explorers of africa.  he was born in a very poor scottish family in 1813 and began work in a cotton mill when he was 10.  he started saving money and was trained to be a doctor.  he began his missionary work in south africa in 1941.  some years later his wife joined him.  he thought that to stop slave trade,  africa needed to be open to trade.  so he started to search for new trade routes.  his first great expedition started in 1853.  he crossed africa on foot from east to west. when he came back to britain in 1856,  he was hailed as a hero.  unfortunately his second expedition on the zambezi river was a disaster, and his wife and many other people died.  his third expedition in 1866 was aimed to find the source of the nile.  he disappeared for five years and everybody thought that he was dead.  he was found in 1871 in a small african town in tanzania.  though he was seriously ill, he refused to leave africa until his mission - to explore rivers - was complete.  livingstone  died in 1873 from malaria and internal bleeding in a small african village in present-day zambia.  his heart  was buried there under a tree near the place where he died. it is livingstone memorial now.  his body was taken to britain and he was buried in the westminster abbey in london.  livingstone's legacy is great.  he made many geographical discoveries.  he was against slave trade.  he was the first to speak of the necessity of education and health care for africans.  livingstone was highly respected by tribe chiefs and local people in africa.