These nets are recognized by medical experts as the best hope for 22 the spread of malaria－Cambodia's most deadly disease. 23 the Health Ministry and the Malaria Center, The CAMBODIA DAILY will distribute the nets to the most 24 areas of the country. 25 to this campaign and save three lives for only $5, send your donation to: American Assistance for Cambodia, P.O.
答案：(C) To contribute
句首的 To contribute… and save… 是不定詞片語表目的，修飾後面的祈使句 send your donation to…；Contribute 會造成兩個祈使句相連而句構斷裂，Contributing 當主詞則無動詞可配，For contributing 用於說明物品用途，都不合。
主要子句 send your donation to… 是祈使句，你看到句首要填一個動作，直覺挑原形 Contribute——這個直覺有來源：祈使句本來就用原形開頭，規則沒錯。錯在邊界：那樣一來前後就變成兩個完整的祈使句只靠一個逗號黏在一起。英文不允許，這個錯誤叫 comma splice（逗號黏合）——兩句中間必須有連接詞，或改用分號、句號。中文可以一路逗號到底，英文不行。檢驗法：把逗號兩邊各自唸一次，兩邊都能單獨成句，就是 comma splice。
要讓句子成立，前半必須降級成修飾語。To contribute to this campaign and save three lives for only $5 是不定詞片語表目的：為了盡一份心力、只花五美元救三條命，請把捐款寄到…。目的在前、動作在後；and 連接的是 To contribute 與（to）save，第二個 to 依慣例省略。整篇是募款廣告，最後一句本來就是「為了…，請…」的行動呼籲。
Contributing 放句首會變成主詞，但後面接的是祈使句，沒有動詞配它。For contributing 的 for + V-ing 用來說明「物品的用途」（I need something for storing CDs.）；人做某事的目的要用 to + 原形。contribute 的字根是 trib-「分配、給予」，con-「一起」 + trib-「給」＝ 大家一起出一份。這個家族一句記完：Thousands of strangers contributed what they could, volunteers distributed the supplies overnight, and the rescue became a tribute to ordinary kindness.（數千個素不相識的人各盡所能捐輸，志工連夜把物資分送出去，那場救援成了對平凡善意的致敬。）〔情境取材自 99 課綱參考試卷作文題：鄰國大地震寫信〕
To V…, 祈使句（為了…，請…）、in order to V（為了）、for + V-ing（說明用途）、make a donation to（捐款給）、contribute to（捐助；促成）、distribute（分配）、tribute（致敬）、wipe out（根除）。
The CAMBODIA DAILY is launching a world-wide campaign to wipe out malaria in Cambodia. You can help save three lives for only $5 by supporting this effort. Each and every dollar you contribute will go 21 the purchase of family-sized insecticide-treated mosquito nets costing $5 each. These nets are recognized by medical experts as the best hope for 22 the spread of malaria－Cambodia's most deadly disease.
23 the Health Ministry and the Malaria Center, The CAMBODIA DAILY will distribute the nets to the most 24 areas of the country. 25 to this campaign and save three lives for only $5, send your donation to: American Assistance for Cambodia, P.O. Box 2716, GPO, New York, NY 10116. Credit Card donations are also accepted.