A great many cities are experiencing difficulties which are nothing new
in the history of cities, except in their scale. Some cities have lost their
original purpose and have not found new one. And any large or rich city is __1__
going to attract poor immigrants, who flood in, filling with hopes of prosperity __2__
which are then often disappointing. There are backward towns on the edge of
Bombay or Brasilia, just as though there were on the edge of seventeenth- __3__
century London or early nineteenth-century Paris. This is new is the scale. __4__
Descriptions written by eighteenth-century travelers of the poor of Mexico
City, and the enormous contrasts that was to be found there, are very __5__
dissimilar to descriptions of Mexico City today—the poor can still be __6__
numbered in millions.
The whole monstrous growth rests on economic prosperity, but behind it lies __7__
two myths: the myth of the city as a promised land, that attracts immigrants __8__
from rural poverty and brings it flooding into city centers, and the myth of __9__
The country as a Garden of Eden, which, a few generations late, sends them __10__
flooding out again to the suburbs.
参考答案及解析：
1. new one -> a new one
one在指代前面出现过的可数名词（此处指purpose）时，如果有形容词修饰，前面应加上部定冠词a。
2. filling -> filled
该成分为定语从句的伴随状语，定语从句的主语为关系代词who，指代poor immigrants，与fill是动宾关系，因此用过去分词filled with，表示“充满”。
3. though -> /
本句大意是：在孟买或巴西利亚周边有一些落后的城镇，正如17世纪的伦敦或19世纪初期周边也有一些落后城镇一样。两句之间的连词应该表示比较，“与...相同”，使后一句成为前一句的比较状语从句。连词as意为“像...一样”，前面just强调程度表示“正如，与...相同”。
4. This -> What
将This改为what，引导主语从句，表示“所...的”。
5. was -> were
定语从句关系代词that的先行词为the enormous contrasts，因此，从句谓语动词要用复数。
6. dissimilar -> similar
从破折号后面的解释性句子the poor can still be numbered in millions可以看出，两种描述是相似性，所以dissimilar是与上下文相矛盾的。
7. lies -> lie
注意but得分句是一个完全倒装句，介词短语behine it提前，真正的主语是two myths，主谓颠倒，因此，该句的谓语要用复数形式。
8. that -> which
9. it -> them
该词在句中代替的是前面提到的immigrants，因此要讲单数人称代词改为复数代词。
10. late -> later