单项选择题
One of the serious weaknesses in American economy in the 1920s was（）
A.uncontrolled speculation in the stock market B.tariff protection C.huge profits of big businesses D.too much control over the banking system
单项选择题 Sacco and Vanzetti were sentenced to death and executed because（）
单项选择题 typically represented the world pattern between the two world wars（）
单项选择题 The essence of the Paris Peace Conference was（）
