公共英語三級難點(diǎn)句型分析：非謂語動詞

【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】本句是一個簡單句，為一個主系表結(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。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;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。