四级作文题目：How to Solve the Housing Problem in Big Cities
　　The shortage of housing in big cities is one of the most serious problems of modern living. Increasing numbers of people are finding it difficult to conduct normal family and work duties because they either have nowhere to live or their houses are inadequate. This is a problem that requires an urgent solution because it leads to social unrest and economic inefficiency.
　　Some people suggest that the solution to the problem is to build more high-rise apartments, others are in favor of underground housing areas. I prefer the first idea, because it is cheaper to build above ground than below. Besides, people prefer to live in the open air and see the sunshine.
　　The second idea is not practical. One reason for this is that it is dangerous to construct living places under streets and buildings. Another reason is that it would take too much time to carry out, and in the meantime the number of people waiting for houses would increase, thus making the problem worse.