“2015中国(湖南)非公有制经济论坛”于2015年9月7日在长沙开幕，非公有制经济现场签约项目30个，总金额237.38亿元人民币，涉及现代服务、先进制造、农业产业化和基础设施建设等领域。这说明我国非公有制经济（  ）

①是社会主义经济制度的基础②是我国经济社会发展的重要基础

③是社会主义的根本经济特征④是社会主义市场经济的重要组成部分

人体内的细胞与外界气体进行气体交换要经过（  ）

完形填空

    Walt Whitman was a famous American poet (诗人). He was born 1 Mary 31, 1819, in Long Island. There were nine2 in his family, and he was the second. 3 he was four years old, his family moved to Brooklyn because his family was too poor. His childhood was restless (不安宁的) and unhappy. 4 the age of 11, he left school. Then he began to 5 a job to help his family. As a young man, Whitman 6 a school teacher, a printer and a newspaper reporter. He was 7 years old when he published his first book of poetry (诗集) in 1855. He 8 itLeaves of Grass. It 9 only twelve poems. The new form of his poetry 10 many people. Whitman was poor and weak during the last years of his life. He died in 1892.