同學生做 UE 1997 Section C 閱讀理解，文章標題為 "The Asian Challenge: British Member of Parliament David Howell contrasts East with West" ，文中 41 至 45 行這樣寫：

So, the prospect emerges not just of richer Asian countries with far better public amenities, but of states with a cleaner environment and more reliable power supplies than Western governments for decades to come.

有學生看不懂這個英語句子，不明白動詞 emerge 後為何會接介詞 of ，而非 from 。今日我就為讀者解讀這句子，並看看英語裡頭一種語法現象，從而解答以上疑問。

可喜的是，我的學生知道動詞 emerge 後可以接介詞 from ，表達東西從哪兒現出，例如：

The sun emerged from behind the clouds.
The world is slowly emerging from the recession.
What eventually emerged from the election disaster was a realization that it was time for change.

不過，在我們要討論的那個句子中，作者並非要說前景或展望 (prospect) 從何而來，而是要說明怎麼樣的一個前景 the prospect of what 出現了，所以動詞 emerge 不帶介詞 from ，而是名詞 prospect 帶介詞 of 。簡單來說，上面那個句子的結構如下：

So, the prospect of X and Y emerges.

當中， X 等於 richer Asian countries with far better public amenities ，而 Y 等於 (Asian) states with A and B ﹝當中 A 即是 a cleaner environment ，而 B 則是 more reliable power supplies ﹞。

換句話說，語法上，介詞詞組 of X 是名詞 prospect 之補語 (complement) ，用來補充 prospect 的意思，而不是動詞 emerges 之補語。

那麼，為什麼這個作名詞 prospect 補語之介詞詞組 of X 會跟它的名詞中心語 (head) prospect 分開呢？ 原來，英語裡頭有一個語法現象，稱之為外位結構 (extraposition) ，在某些情況下，句子中的一個組成成分 (constituent) ，例如一個介詞詞組或一個關係子句 (relative clause) ，由原來的位置向右移位，通常移到句子的末端。允許外位結構出現的情況包括要句子說起來順口一點，及避免句子中間位置過重、尾則過輕。不妨看看以下例子：

  1. a similar book to this one
    移位前： a similar to this one book
  2. How fond are you of Sally?
    移位前： How fond of Sally are you?
  3. A review appeared of Friedman’s latest book on the cultural differences between East and West.
    移位前： A review of Friedman’s latest book on the cultural differences between East and West appeared.
  4. Although no rules exist about eating or drinking in the classroom, one does about chewing gum.
    移位前： Although no rules about eating or drinking in the classroom exist, one does about chewing gum.
  5. After the dinner, a musician arrived who was hired yesterday for the wedding where many celebrities were invited, and performed a piano concerto in front of the audience.
    移位前： After the dinner, a musician who was hired yesterday for the wedding where many celebrities were invited arrived, and performed a piano concerto in front of the audience.

上面幾個例子中，黑色粗體字表示移位了的 (extraposed) 句子組成成分，它們都跟各自的中心語﹝加底線部分﹞分開。

我們要討論的那個句子，其實是要說：「展望將來，在未來幾十年，亞洲國家不但會富裕起來、擁有更佳的公共設施，而且與西方國家相比，環境會更清潔、能源供應會更可靠。」如果不運用外位結構 (extraposition) ，句子會變成：

So, the prospect of not just richer Asian countries with far better public amenities but states with a cleaner environment and more reliable power supplies than Western governments for decades to come emerges.

個人認為，不使用外位結構，句子既寫得不夠漂亮，讀起來也不夠順口，原因是句子中間位置變得累贅。緊記一點，英語傾向句子尾重、中間輕。