Whatisthemainpurposeofthistext?
A.Tocallonpeopletopaymoreattentiontohousingproblems.
B.Toprovethatsomestandardsareneededforaffordablehousing.
C.Toasksocietytohelphomelesspeopleandlow-incomefamilies.
D.Tointr oducehealthy,environmentallyclever-andaffordablehousing.
正确答案:D


