【難句】The energy used to separate oxygen from air before burning is almost as great as that needed to filter out nitrogen afterwards, leading to a similar loss of efficiency. (The Economist Nov. 30, 2006)。

　　【結(jié)構(gòu)分析】本句是一個(gè)簡(jiǎn)單句，為一個(gè)主系表結(jié)構(gòu)The energy is almost as great as that needed to filter out nitrogen afterwards，使用了as…as…結(jié)構(gòu)，其中被比較的對(duì)象that needed to filter out nitrogen afterwards中，that指代上文的energy，過去分詞結(jié)構(gòu)needed to…作后置定語體現(xiàn)被動(dòng)。其中主語energy由過去分詞結(jié)構(gòu)used to separate oxygen from air before burning 作后置定語體現(xiàn)被動(dòng);句末的現(xiàn)在分詞結(jié)構(gòu)leading to a similar loss of efficiency作全句的結(jié)果狀語。

　　【參考譯文】 燃燒前將氧氣從空氣中分離所需的能源幾乎不亞于上述將氮?dú)膺^濾所需的耗費(fèi)，這就使得兩者在效率損失上不相上下。