听力原文： From 1946 until 1954, the Vietnamese had struggled for their independence from France during the First Indochina War./ At the end of this war, the country was temporarily divided into North and South Vietnam./North Vietnam came under the control of the Vietnamese Communists who had opposed France and who aimed for a unified Vietnam under Communist rule./ The South was controlled by Vietnamese who had collaborated with the French./The United States became involved in Vietnam because it believed that if all of the country fell under a Communist government, Communism would spread throughout Southeast Asia and beyond./This belief was known as the" domino theory./" The U. S. government, therefore, supported the South Vietnamese government./This government' s policies led to rebellion in the South./Finally, however, the United States failed to achieve its goal,/and in 1975 Vietnam was reunified under Communist control;/in 1976 it officially became the Socialist Republic of Vietnam./
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