built录音中的was drained是题目的原词复现，to house是题目to provide land的同义替换，故空格处填入built。

In the last few weeks, we’ve been looking at various aspects of the social history of London, and this morning we’re continuing with a look at life in the area called the East End. I’ll start with a brief history of the district, and then focus on life in the first half of the twentieth century.
Back in the 1st to the fourth centuries AD, when the Romans controlled England, London grew into a town of 45,000 people, and what’s now the East End — the area by the river Thames, and along the road heading north-east from London to the coast — consisted of farmland with crops and livestock which helped to feed that population.
The Romans left in 410, at the beginning of the fifth century, and from then onwards the country suffered a series of invasions by tribes from present-day Germany and Denmark, the Angles, Saxons and Jutes, many of whom settled in the East End. The technology they introduced meant that metal and leather goods were produced there for the first time. And as the East End was by the river, ships could transport goods between there and foreign markets.
In the 11th century, in 1066 to be precise, the Normans conquered England, and during the next few centuries London became one of the most powerful and prosperous cities in Europe. The East End benefited from this, and because there were fewer restrictions there than in the city itself, plenty of newcomers settled there from abroad, bringing their skills as workers, merchants or money-lenders during the next few hundred years.
In the 16th century the first dock was dug where ships were constructed, eventually making the East End the focus of massive international trade. And in the late sixteenth century, when much of the rest of England was suffering economically, a lot of agricultural workers came to the East End to look for alternative work.
In the seventeenth century, the East End was still a series of separate, semi-rural settlements. There was a shortage of accommodation, so marshland was drained and built on to house the large numbers of people now living there.
By the nineteenth century, London was the busiest port in the world, and this became the main source of employment in the East End. Those who could afford to live in pleasant surroundings moved out, and the area became one where the vast majority of people lived in extreme poverty, and suffered from appalling sanitary conditions. That brief outline takes us to the beginning of the twentieth century, and now we’ll turn to housing.
At the beginning of the century, living conditions for the majority of working people in East London were very basic indeed. Houses were crowded closely together and usually very badly built, because there was no regulation. But the poor and needy were attracted by the possibility of work, and they had to be housed. It was the availability, rather than the condition, of the housing that was the major concern for tenants and landlords alike.
Few houses had electricity at this time, so other sources of power were used, like coal for the fires which heated perhaps just one room. Of course, the smoke from these contributed a great deal to the air pollution for which London used to be famous.
A tiny, damp, unhealthy house like this might well be occupied by two full families, possibly including several children, grandparents, aunts and uncles.
Now, before I go on to health implications of this way of life, I’ll say something about food and nutrition.