unless they succeed，the　yield gains of the green revolution will be largely lost even if the genes in　legumes that equip those plants to enter　into a symbiosis with nitrogen fixers　are identified and isolated，and even if　the transfer of those gene complexes，once they are found， becomes possible. (4)

除非他們能取得成功，不然的話，綠色革命的產(chǎn)量收益將在很大程度上損失殆盡，即使豆科植物中使這些植物有條件進(jìn)入到與固氮細(xì)菌共生關(guān)系的基因可被辨識(shí)出來(lái)和分離開(kāi)來(lái)的話，且即使這些基因綜合體(gene complex)，一旦被發(fā)現(xiàn)之后，其移植得以成為可能的話。

難句類型：

復(fù)雜修飾、插入語(yǔ)

解釋：

主句比較簡(jiǎn)單，而后面跟著的由and連接的兩個(gè)表示讓步的條件狀語(yǔ)從句就相對(duì)復(fù)雜，第一個(gè)從句是用一個(gè)修飾主語(yǔ)的定語(yǔ)從句that equip those plants to enter into a symbiosis with nitrogen fixers把主謂隔開(kāi);第二個(gè)從句則運(yùn)用了插入語(yǔ)once they are found把主謂隔開(kāi)。

意群訓(xùn)練：

unless they succeed，the　yield gains of the green revolution will be largely lost even if the genes in　legumes that equip those plants to enter　into a symbiosis with nitrogen fixers　are identified and isolated，and even if　the transfer of those gene complexes，once they are found， becomes possible.