How did China get to be a permanent member with veto power in the security council? As far as I know China wasn't a member until the seventies, when they took Taiwans seat. If they achieved this in the seventies, why wasn't other countries protesting decision? And what was the view of the USSR? China and the USSR had a bad relationship in the seventies, had they not?
You have to be pretty careful with the China/Taiwan nomenclature generally, but particularly when talking about the UN. China (as the Republic of China) was a charter member of the UN in 1945, as one of the victorious powers of the Second World War — that's from whence it derives its position as a permanent member of the Security Council.
After the nationalist defeat in the Chinese Civil War in 1949, the Kuomintang government fled to Taiwan and formed a government-in-exile; the Republic of China — as it is still called today — maintains that it is the legitimate government of all of China. Meanwhile, on the mainland, the communists formed the People's Republic of China, and claim sovereignty over Taiwan.
Over the course of the subsequent decades, the PRC repeatedly attempted, by way of an annual motion brought before the General Assembly, to have the ROC expelled from the UN and the PRC seated in its place. The US, ROC and their allies managed to block these efforts until 1971, when the PRC (supported by a coalition of communist, Non-Aligned and some European states) succeeded in passing Resolution 2578.
Quite simply, the ROC found themselves politically outmaneuvered: the vote came at a time when Richard Nixon was attempting to normalise US relations with the PRC (the resolution passed less than four months before his historic visit to China), and a US veto would have scuttled that process.