1.一樓有文抄公之嫌.先簡要回答如下：
1）如果not only...but also...連接的是一個(gè)句子之中的并列成分,則無須倒裝.
至于具體例句,請參考一樓.
2）但是如果not only...but also...連接的是兩個(gè)并列的句子,則要求前句采用部分倒裝,后句無須倒裝.
樓主所給的例句即是用not only...but also...連接兩個(gè)并列句：food production is important和taking care of the environment (is important),其中后句采用了省略語法.
2.至于部分倒裝怎么倒的問題,樓主的關(guān)于陳述句變一般疑問句的知識不知道掌握重復(fù)否?
部分倒裝就等同于對該句進(jìn)行一般疑問句的變化,即把該句所含的be動(dòng)詞/助動(dòng)詞/情態(tài)動(dòng)詞提前.
如：not only (food production is important)
變化成：not only (is food production important)
再如：not only (I can play soccer)
變化成：not only (can I play soccer)
最后如：not only (he likes sports)
變化成：not only (does he like sports)
3.此例句必須倒裝,原因在于英語語法的規(guī)定是這樣的：
如果某句把否定詞或含有否定詞的短語（包括not only）提前至句首時(shí),則該句必須采用部分倒裝.
再如：I have never been to Beijing.
= Never have I been to Beijing.
4.最后,需要提醒樓主的是：如果not only沒有提前至句首或not only...but also...不引導(dǎo)并列句時(shí),則不必倒裝.
即該例句可以直接寫為：
Not only (is food production important) but also taking care of the environment.
= Not only food porduction but also taking care of the environment is important.
5.補(bǔ)充：這題之所以可以不倒裝,是因?yàn)檫@是一種不太正式的說法,即：
Not only food production is important but also taking care of the environment.
= Not only food production but also taking care of the environment is important.
因?yàn)橹皇侵髡Z的并列,可以不算是句子的并列,所以它可以不用倒裝.
也就是說,在不是很正式的情況下,像這樣連接兩個(gè)分句且前一個(gè)完整而后一個(gè)有省略時(shí),前一句可以不倒裝.