Peoplein London in the mid-nineteenth century greatly feared cholera. Atthis time doctors...........(believed) that cholera ......... (circulated)through the air, and ..........(did not realize) that all the time rawsewage .........(was entering) water supply, and that the disease........(spread) through the domestic water system. Although in the 17thand 18th centuries London ....... (possessed) a water supply system and asewage system which were the changing situation. Broken water pipes andsewage pipes often ......(flew) into one another, and most sewage.........(ended up) in the River Thames, which was the main source ofdrinking water for thousands. Between 1831 and 1867 a series of severeoutbreaks .........(occured). In the outbreak of 1848-49, there were over30000 cases of the disease in London, and 15000 people ..........(died).By the mid 1860s the situation .........(had improved) mainly because by thenengineers ........(had been working on) the construction of a completely new sewagesystem, which they .........(completed) in 1875, and which is still inuse today.
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