今天我們來看這樣一個句子：
The central state, though often very rich and very populous, was intrinsically fragile, since the development of new international trade routes could undermine the monetary base and erode state power, as occurred when European seafarers circumvented Middle Eastern merchants after Vasco da Gama's voyage around Africa in the late fifteenth century opened up a southern route.( TPO16,56)
populous /'pɒpjʊləs/ adj. 人口多的，人口稠密的
intrinsical /in'trinsik,-kəl/ adj. 本質(zhì)的，內(nèi)在的
undermine /ʌndə'maɪn/ vt. 逐漸削弱或暗中破壞;
erode /ɪ'rəʊd/ vt. )侵蝕，腐蝕
seafarer /'siːfeərə/ n. 船員，水手
monetary /'mʌnɪtɛri/ adj. 貨幣的，錢的
circumvent /sɝkəm'vɛnt/ vt. 設法克服或避免(某事物);規(guī)避，回避
我是分界線，大家先一遍速讀看是否理解
The central state, (though often very rich and very populous),was intrinsically fragile, (since the development of new international trade routes could undermine the monetary base and erode state power), (as occurred)(whenEuropean seafarers circumvented Middle Eastern merchants)(after Vasco da Gama's voyage around Africa in the late fifteenth century opened up a southern route.) ( TPO16,56)
托福閱讀長難句100句分析：
這句話的主干就是：
The central state was intrinsically fragile
修飾一：(though often very rich and very populous)，插入語
中文：雖經(jīng)常非常富有且人口眾多
修飾二：(since the development of new international trade routes could undermine the monetary base and erode state power)，從句
中文：因為新的國際貿(mào)易線路的發(fā)展能破壞貨幣基礎并腐蝕國家權力
修飾三：(as occurred) ，從句
中文：就如同發(fā)生
修飾四： (when European seafarers circumvented Middle Eastern merchants) ，中文：當歐洲水手們就避開了中東商人
修飾五：(after Vasco da Gama's voyage around Africa in the late fifteenth century opened up a southern route.) ，從句
中文：在十五世紀晚期Vasco da Gama繞過非洲的航行開辟了南部航線后
托福閱讀長難句100句參考翻譯：
這個中央帝國，雖經(jīng)常非常富有且人口眾多，但本質(zhì)脆弱，因為新的國際貿(mào)易線路的發(fā)展能破壞貨幣基礎并腐蝕國家權力，就如同在十五世紀晚期Vasco da Gama繞過非洲的航行開辟了南部航線后，歐洲水手們就避開了中東商人而使用南部航線了。
這個句子的主要修飾成分就是從句和插入語，大家務必想清楚，每一個修飾成分修飾的是什么，才能看清楚這個句子的結構。