don't know → dunno
this year → thish-yer
last year → las-cher
because; of course → 'cos
must have –→ must of
lot of → lotta
rock and roll → rock'n'roll
What is the matter? → Whatsa matter?
I'll stay in Beijing until the end of next week-—(because) I want to discuss the matter with Mr. Zhu.
(1) 書面體：Known abroad as kungfu or martial arts,wushu has been practiced for several thousand years by the working people in China.
口語體：Wushu is known abroad as kungfu or martial arts;it has been practiced for several thousand years by the working people in China.
(2) 書面體： While some old contradictions and confrontations have disappeared, new ones have cropped up, rendering our world neither tranquil nor peaceful.
口語體： While some old contradictions and confrontations have disappeared, new ones have cropped up; our world is neither tranquil nor peaceful.
(3) 書面體：The gap between the North and the South continue to widen, with the rich countries becoming richer and the poor poorer.
口語體： The gap between the North and the South continue to widen. The rich countries are becoming richer and the poor poorer.
(4) 書面體：The capital of the People's Republic of China,Beijing is the country's political, economic, and cultural center.
口語體：Beijing is the capital of the People's Republic of China and the country's political, economic, and cultural center.
(1) 書面體：Over the long years,whichever exploiting class that controlled national or local power, irrespective of the nationality to which it belonged, invariably pursued a policy of national oppression against the other
nationalities and brought misery to people of all the nationalities, with the smaller ones suffering the most severely.
口語體：Over the long years,no matter which exploiting class controlled national or local power, and no matter which nationality it belonged, it always oppressed and brought misery to the people of all the nationalities. The smaller ones suffered the most.