一道完型填空In the old days, London was k____ (1) as a city of fog

一道完型填空
In the old days, London was k____ (1) as a city of fog.. The fog was as thick as peasoup . London’s fog was c_____(2) by factory smoke , so it was called “smog”. The smog was so thick that car and bus drivers could h_____(3) see the road in front of them even during the daytime . People had to w____(4)”smog--masks” over their faces when they went out.
In December 1952,a very thick dark c_____(5)came down over the city. It was the w____(6)somg Lon—dowers had ever had. Nearly fifty people died in road acci-dents. Many more people b_____(7) very unhealthy .After three weeks,the smog began to l____(8)slowly. Life in London came back to normal（正常）.But not long after that, over 4000 people died as a r______(9) of the smog.
In 1956, the British s______(10) burning coal in houses and factories in the city. London’s air got cleaner.