The Amazons fight on 28 they seize the pupae of the raided nest.
答案：(D) until
語意「亞馬遜蟻持續戰鬥，直到牠們奪取幼蟲為止」，until（直到）符合；and／but 都不合，after（在……之後）語意方向也不合（應該是「戰鬥直到奪取」不是「奪取之後戰鬥」）。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
四個選項都能連接兩個動作，而 and（然後）讀起來最順——「戰鬥，然後奪走蛹」。但那樣就漏掉了 fight on 裡那個 on 的意思。
先看空格前面的動詞：The Amazons fight on ___ they seize the pupae（亞馬遜蟻持續戰鬥……牠們奪走蛹）。fight on 的 on 是「繼續下去」的意思（go on 繼續、carry on 持續、hold on 撐住），所以前半句強調的是戰鬥一直持續。既然是持續的動作，就需要一個終點，而表示「一直到……為止」的是 until，整句是「亞馬遜蟻持續戰鬥，直到牠們奪走了對方巢裡的蛹為止」。這一格與 90 年第 24 題是同一個用法——那裡是 an alarm that gets increasingly louder until it is turned off（鬧鈴越來越大聲，直到被關掉為止），兩題都是「一個持續的過程延續到某個終點」。（83 年第 39 題的 It was not until ... that ... 則是 until 的另一種考法，那是強調句型的一部分。）
and（然後）：只是把兩個動作並列，表達不出「持續到那一刻為止」的意思，也用不到 fight on 的 on。but（但是）：轉折，但奪走蛹正是牠們戰鬥的目的，方向一致。after（在……之後）：時間順序反了——應該是「戰鬥直到奪到蛹」，不是「奪到蛹之後才戰鬥」。
fight on until（持續戰鬥直到）、go on（繼續）、carry on（持續進行）、seize（奪取、抓住）、pupae（蛹，pupa 的複數）、in time（不久之後）。
Some species of ants keep slaves. Probably the best known for the practice is the large brownish-red Amazon ant. A slave raid starts with an assembly of the Amazon warriors outside their own nest. Then, almost 26 at a given signal, the group begins to march toward the colony 27.
When the Amazons reach the nest of their intended victims, a fierce battle may take place. The Amazons fight on 28 they seize the pupae of the raided nest. They carry these back home. In time the pupae develop into adults and spend their lives working for the Amazons.
The Amazons are completely dependent on their slaves 29 their sharp jaws, so well suited for fighting, are useless in taking care of larvae or for digging. Also, the masters become so lazy that, after a while, they lose their muscles, and they become too weak 30 to feed themselves. Finally, they become so unhealthy that they die.