【是這樣】：
說話人為了強調(diào)、突出Unsurprising這個詞,使之更為醒目,前面省略了“It is”.完整的應(yīng)該是：
“It is unsurprising then that China should have a long history of mucking about in Korean politics,a history which has often brought it into conflict with that other great Eastern power,Japan.”
“a history which has often brought it into conflict with that other great Eastern power,Japan.”是a long history的同位語.“which has often brought it……”為a history的定語從句.中間的it是指前句中的“China”.
【整句話的意思是】：
“因此,這絕沒有什么好奇怪的：中國在朝鮮政治（事務(wù)）上糾纏悱惻,原就有著悠久的歷史,一部常常使之與另一東方列強——日本,陷入沖突之中的歷史.”