The problem of the homeless has become very serious in the United States.Almost in every community, you can find homeless people.An ironical case is: in November, 1993,a woman died on a street in Washington, D.C.,the nation's capital,and she died at a bus-stop across the street from the US Department of Housing and Urban Development.People become homeless for various reasons.(1)_______________________.Others have mental disorders,or are addicted to drugs or alcohol,and there are not enough centres to care for them.As ways to help these people,the federal government and many communities have set up all kinds of projects.(2)_______________________.Some communities have opened centres that offer services for as many as 700 people.The homeless can stay as long as they want.People are making efforts to solve the problem.However, it will not be easy,(3)_______________________________.