10. Read the text. Four sentences have been removed from it. Choose from sentences A-E the one which fits each gap (1-4). There is one extra sentence which you do not need to use

10. Read the text. Four sentences have been removed from it. Choose from sentences A-E the one which fits each gap (1-4). There is one extra sentence which you do not need to use

A. The amount of pressurization is called boost.

B. Water circulates through passages around the cylinders and then travels through the radiator to cool it off.

C. The valve train consists of the valves and a mechanism that opens and closes them.

D. In most cars, oil is sucked out of the oil pan by the oil pump.

E. Most of these subsystems can be implemented using different technologies, and better technologies can improve the performance of the engine.

Engine subsystems

    An internal combustion engine has a number of systems that help it do its job of converting fuel into motion. 1____________________________. Here is a look at some of the different subsystems used in modern engines.        

Cooling system. The cooling system in most cars consists of the radiator and water pump. 2_________________________. In a few cars as well as most motorcycles and lawn mowers, the engine is air-cooled instead of water. Air-cooling makes the engine lighter but hotter, generally decreasing engine life and performance.

    Air intake system. Most cars are normally aspirated, which means that air flows through an air filter and directly into the cylinders. High-performance engines are either turbocharged or supercharged, which means that air coming into the engine is first pressurized (so that more air-fuel mixture can be compressed into each cylinder) to increase performance. 3__________________________. A turbocharger uses a small turbine connected to the exhaust pipe to spin a compressing turbine in the incoming air stream. A supercharger is connected directly to the engine to spin the compressor.

    Lubrication system. The lubrication system makes sure that every moving part in the engine gets oil so that it can move easily. The two main parts needing oil are the pistons (so they can slide easily in their cylinders) and any bearings that allow things like the crankshaft and camshafts to rotate freely. 4_______________________. Then it runs through the oil filter to remove any grit, and then injected under high pressure onto bearings and the cylinder walls. The oil then flows down into the sump, where it is collected again and the cycle repeats.