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)系的基因可被辨識出來和分離開來的話，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

解釋：

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

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.