“三座大山”
“three great mountains which weighed on the backs of the Chinese people—imperialism,feudalism and bureacrat-capitalism”
三座大山
the three big mountains(imperialism,feudalism and bureaucrat-capitalism)(帝國主義、封建主義和官僚資本主義)
推翻了壓在中國人民頭上的～removed the three big mountains of imperialism,feudalism and bureaucrat-capitalism oppressing (or weighing down upon)the Chinese people before liberation