In 1921 the British signed the Anglo-Irish Treaty to_______________ .
A、start a civil war
B、keep Ireland out of World War II
C、found the Irish Republican Army
D、establish an Irish Free State in Northern Ireland
【正确答案】：D
【题目解析】：1921年，英国人签署了《英爱条约》，建立了爱尔兰自由邦。
