“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)(帝国主义、封建主义和官僚资本主义)
推翻了压在中国人民头上的～removed the three big mountains of imperialism,feudalism and bureaucrat-capitalism oppressing (or weighing down upon)the Chinese people before liberation