250.But those captured were anything but terrorists, most of them illegal immigrants from Central or South America.

英語四級譯文:
被逮捕的并非恐怖主義者，其中大多數是來自中美與南美的非法移民。

四級詞匯講解:
本句的主干是those were anything but terrorists。過去分詞captured為代詞those的后置定語，兩者為被動關系;most of them illegal immigrants from Central or South America對主語those起到了補充說明的作用，其中them指代的就是those，這句還可以替換為非限制性定語從句: most of whom were illegal immigrants from Central or South America。

anything but的意思是“決不，根本不”，屬于肯定形式表達否定含義的情況。如:
The bridge is anything but safe.這橋一點也不安全。

英語四級考點歸納:
其他肯定形式表達否定含義的短語還有:

※ far from意為“遠非...，完全不”。如:
His plan is far from satisfactory.他的計劃完全無法令人滿意。

※ the last+名詞+to不定式/從句，意為“最不……”。如:
That is the last thing to happen.那是最不可能發生的事。

※ fail to意為“無法”。如:
We failed to negotiate with them.我們無法與他們協商。

※ be free from意為“沒有，不”。如:
I was free from work last week.我上個星期沒有上班。

※ let alone意為“更別說，更談不上”。如:
I never know him, let along his family.我從不認識他，更別提他的家人了。

※ in vain意為“徒勞，無法辦到”。如:
She tried to find out the truth, but in vain.她試圖找出真相，但沒做到。