mọi người giúp em với ạ, có giải thích càng tốt ạ. SMOG AND AIR POLLUTION For years London was synonymous with smog, the word coined at the (53)_____ of the 20th century to describe the city’s characteristic blend of fog and smoke. The capital’s “pea-soupers” were caused by suspended pollution of smoke and sulfur dioxide from coal fires. The most (54)_____ affected area was the 19th-century residential and industrial (55)_____ of inner London – particularly the East End, which had the highest density of factory smokestacks and domestic chimney pots and the lowest-(56)______ land, inhibiting dispersal. As recently as the early 1960s, the smokier districts of east Inner London experienced a 30 percent reduction in winter sunshine hours. That problem was (57)______ by parliamentary legislation (the Clean Air Acts of 1956 and 1968) outlawing the burning of coal, combined with the clearance of older housing and the loss of manufacturing. The less visible (58) _____ equally toxic pollutants of carbon monoxide, nitrogen dioxide, ozone, benzines, and aldehydes continue to spoil London’s air. Traffic fumes and other exhausts are (59)______ to become trapped between the surrounding hills and below a stagnant capping mass of warm urban air at an altitude of about 3,000 feet (900 metres), causing immediate increases in eye irritation, asthma, and bronchial complaints. But London’s weather is too (60)_____ for the development of a full-scale photochemical smog of the kind that can build up under the more stable weather conditions of cities such as Los Angeles. 53. A. back B. turn C. next D. gap 54. A. largely B. frequently C. thoroughly D. severely 55. A. ring B. belt C. loop D. tie 56. A. standing B. situating C. lying D. locating 57. A. alleviated B. exalted C. degraded D. abated 58. A. with B. besides C. regarding D. but 59. A. able B. tenable C. liable D. flammable 60. A. wicked B. lethal C. agile D. fickle