【正确答案】
(Student's sample)
With the industry developed, the population in big cities grows very fast. But the urban area is very limited. That's the reasons caused the housing problem in big cities. To tackle this problem, we must figure out some ways, one is, we should build "satellite cities" in the suburbs of big cities to distribute the people working in big cities. Secondly, in order to let the low-income residents to buy their houses, the government should offer some discount. Although this issue is very difficult, so, we should make greater efforts to take all kinds of actions, and I do believe that the housing problem in big cities can be tackled.
(Improved sample)
With the fast development of modern industry, more and more people are flooding into big cities to find jobs, which caused the housing problem in big cities. We have figured out many ways to solve this problem. Firstly, it is a good idea to build "satellite cities" in the suburbs of big cities so that people will be dispersed in a large area. Secondly, in order to meet the housing demand of low-income residents, the government should build more buildings and offer a discount for low-income families to buy their houses. The housing problem is so complicated that we should make further efforts to improve the situation in big cities.